Lothar, mz-forum.com

Electrics of

MZ two-stroke

(with additions to the four-stroke Rotax models from MZ)

Vers. 2015-11-11

Table of Contents

Foreword ................................................. .................................................. .......... 5

0. Preliminary remarks

0.1 Required (electrical) aids ............................................ ...................... 7

0.2 Terms, symbols .............................................. ............................................ 7

0.3 Important terminal designations for vehicle electrics ...................................... 8

0.4 Measurement of voltage, current and resistance with a digital multimeter ........ 9

A DC generator and 6V electrical system

A.1 Field-regulated DC alternator for 6 V vehicle electrical system ........................ 11

A.1.1 Checking the winding resistances

A.1.2 Alternators - function test

A.2 Electromechanical controller (6 V) ......................................... ....................... 16

A.2.1 Mechanical adjustment

A.2.2 Electrical adjustment

A.3 Electronic controller (6 V) ......................................... .................................. 26

A.3.1 Removal of the regulator resistor

A.3.2 Electronic controller - function test

A.4 Contact ignition system (6 V) .......................................... ..................................... 29

A 4.1 Overview

A.4.2 Contact, ignition capacitor

A.4.3 Ignition coil

A.4.4 Ignition cable, connector and plug

B Three-phase generator and 12 V electrical system

B.1 Field-regulated three-phase alternator for 12 V vehicle electrical system ......................... 37

B.1.1 Checking the winding resistances

B.1.2 Alternators - function test

B.1.3 The field winding fuse 2A "slow"

B.2 Rectifier block .............................................. ............................................ 41

B.2.1 Circuit

B.2.2 Function test

B.3 Electromechanical controller (12 V) ......................................... ...................... 44

B.3.1 Mechanical adjustment

B.3.2 Electrical adjustment

B.4 Electronic controller (12 V) ......................................... ................................. 49

B.4.1 Replacement of electromechanical by electronic plus regulator

B.4.2 Function test for electronic plus controller

B.4.3 Rectifier / electronic minus regulator on the last 2T models

B.4.4 Function test of rectifier / electronic minus regulator

B.5 Ignition system (12 V) .......................................... .............................................. 56

B.5.1 Contact ignition system

B.5.2 Electronic ignition system with Hall sender

C Permanently excited 12 V three-phase generator (Rotax)

C.1 Three-phase generator - function test ............................................ ................ 60

C.2 Rectifier / controller block - function test .......................................... .......... 62

C.3 Electronic tachometer (eDZM) .......................................... ............. 64

C.4 Electronic ignition (CDI, Nippondenso) ........................................ ......... 65

V Miscellaneous

V.1 Cable connections .............................................. .......................................... 67

V.1.1 Cable resistance and voltage drop

V.1.2 Voltage drops in the vehicle electrical system

V.2 Accumulator .............................................. .................................................. ... 71

V.2.1 Characteristic values and properties

V.2.2 Function test

V.2.3 Check operating conditions in the vehicle electrical system

V.4 Some typical error patterns ............................................ ............................. 80

V.4.1 Battery is not sufficiently charged, engine cuts out when idling

V.4.2 Charge control does not go out or is glowing

V.4.3 Ignition fails

V.5 Horn .............................................. .................................................. .............. 83

V.6 Electronic tachometer ............................................. ........................ 87

V.7 The setting of the breaker ignition ........................................... ........... 91

V.8 Vehicle light bulbs ............................................ ........................................ 98

Z Appendix

Z.1 Circuit of the electronic 6 V regulator MZ ELEKTRONIKUS ................ 101

Z.2 Electronic controller for permanently excited Rotax-LiMa ............................. 102

Z.3 P ermanent-excited LiMa with rectifier / regulator and ignition ................. 103

Z.3.1 Regulator / rectifier for 2-phase LiMa

Z.3.2 Electronic ignition (CDI, similar to vape)

Z.3.3 Rotax: Electronic ignition (CDI, Nippondenso)

Z.4 12V regulator circuit L 9480 in the ETZ ....................................... .......... 112

Z.4.1 Properties of the L9480 control circuit

Z.4.2 Measurements on the L9480 circuit

Z.4.3 Installation in the vehicle electrical system and behavior

Z.5 Battery chargers and their properties ........................................... ...... 121

Z.6 Electronic flasher unit 12V (FER GmbH) ........................................ ..... 126

Z.7 Ignition position: conversion from (° before TDC) to (mm before TDC) ......................... 128

Bibliography ................................................. ..................................... 131

Preface

In this text, important components of the vehicle electrics of the MZ two-stroke engines up to 1989 are described with regard to their function and testing. Some topics relating to the electrics of the four-stroke Rotax models have also been included. The purpose of this document is to provide “help for self-help” when analyzing malfunctions or adjusting or repairing them. To do this, however, a minimum of electrical engineering and / or metrological knowledge is required, which can easily be acquired as an educated and willing MZ driver even at an advanced age. However, if there is an insurmountable aversion to anything electrical, it is better to keep your hands off it.

The representations are basically structured in such a way that each assembly can be tested independently of the rest of the on-board electrical system. One or the other section may also help to better understand the operation of certain electrical devices in the vehicle.

You can improve your own skills if the tests, measurements or adjustments described are first tried out on functioning components. Perhaps there is a rectifier plate, an alternator or a regulator in the spare parts box, which can be used as objects for practice measurements without causing damage.

The specification of data, inspection, measurement and test methods often goes beyond the scope known from the literature, in that a number of missing or inaccurate information has been replaced by measurement or empirical values obtained by the "young vehicle electrician" without information such as "sufficiently large", "usual" or "sufficiently small" to leave in the dark. In this respect, small adjustments will probably not be missing here and there in the future. Since there are no technological documents from the production period from which the target parameters of the product development at that time could be read, measurements had to be carried out on individual objects for some information in the hope that these would meet the typical values.

The author is therefore happy to receive any critical or additional information, suggestions for improving or expanding the information. Where is something written incomprehensibly or not clearly formulated? Confirmatory reports of measurements are also welcome. The more that comes together in this way, the more secure the information becomes.

Ultimately, the long-term, interested follow-up of electrical problems in the Internet forum for MZ drivers gave the impetus for this presentation of selected electrical problems on two-stroke MZs. Error descriptions of helpless MZ drivers, collective remote diagnostics, factual and belief discussions as well as valuable hints and advice from Foristi that I received, expanded and deepened the electrical knowledge about our MZs, which is certainly not possible without the Internet on this scale would.

I therefore dedicate this work to the MZ forum: www.mz-forum.com

Anyone who has found the tips and hints listed here helpful in solving problems can return the favor with a donation for running the forum server. Information is available on the portal page of

www.mz-forum.com.

Exclusion of liability: No liability whatsoever is accepted for damage caused by the practical implementation of the instructions.

If the rights of third parties have been unknowingly violated, this must be reported immediately so that the corresponding content can be removed.

The work or the content

may

· Given to the author (Lothar, mz-forum.com) are made publicly available (in the WWW is only the link allows the source through which the always current version can be reached:

http://pic.mz-forum.com/lothar/ELEKTRIK/MZ-Elektrik.pdf)

not allowed

· Be used for commercial purposes

not allowed

· Edited, modified or changed in any other way

Lothar, November 23, 2015

0. Preliminary remarks

0.1 Required (electrical) tools

· 3 ½ digit digital multimeter , eg HP-760B

· Various 6 V or 12 V car light bulbs as test equipment or as a replacement for loads.

· Adjustable voltage source 0-15V / 0-3A, e.g. Peaktech 6080

In some cases a fixed voltage source is sufficient, eg an external 6 V or 12 V battery or the on-board battery itself. The specified device can also be used as an ideal battery charger due to the continuously adjustable voltage and current limitation.

0.2 Terms, symbols

Nominal voltage in the 12 V on-board voltage system: 13.2 V.

corresponding to the 6 V on-board voltage system: 6.3 V.

(the service life specification of vehicle light bulbs in ECE R37 relates, for example, to this nominal voltage)

LiMa = Abbreviation for alternator or voltage generator

Ground = electrical reference point on the motor housing (D-) or at a central ground point of the wiring harness.

Circuit symbol for ground connection: (for MZ applies: ground = negative pole)

Unless otherwise specified, voltages are always measured against ground.

General direct or alternating voltage source (e.g. mains-operated voltage supplies, batteries or accumulators), polarity indication by +/- or arrow orientation:

Special: electrochemical DC voltage source (battery, accumulator)

0.3 Important terminal designations in vehicle electrics

(1) Ignition coil to the break contact

(15/54) Switched positive lead from the ignition light switch / brake light

(30) Battery plus (even after a fuse, if present)

(31) Battery minus (even after a possibly existing fuse),

equivalent to mass or D-

(31b) Switched ground to the horn

(49) Input of a two-pole flasher unit (plus side)

(49a) Output of a two-pole flasher device (minus side)

(51) Controller output to battery plus (sometimes also referred to as B + )

(56a) high beam

(56b) low beam

(58) Tail light, parking light

(61) LiMa-side connection of the charge indicator light

D + Positive pole of the direct current LiMa or positive terminal after

Three-phase rectifier

D- Negative pole of the direct current LiMa, generally also for the designation

the vehicle mass used

DF + external connection of the excitation field winding to the controller

often plus controlled systems only as DF referred

DF- second end of the field winding, in plus-regulated systems in the

LiMa clamped to ground

U, V, W Connection terminals of the three-phase LiMa

B + controller output after battery plus for electronic controllers,

corresponds to (51)

0.4 Measurement of voltage, current and resistance with a digital multimeter

Usual designation of the input sockets

COM: Connection of the minus measuring cable

VΩmA: Connection of the (plus) measuring cable for voltage [V], resistance [Ω] or current measurement [mA]. The additional label "FUSED 200mA MAX" means that the current measuring path is internally fused with 200 mA to protect the device.

UNFUSED 20Amax: Connection of the measuring cable for current measurement in the range from 200 mA to 20 A. The device is not protected in this area, exceeding the maximum current (here eg 20 A) will destroy the device.

Safety rule: Always start measurement with the largest measuring range!

Voltage measurement

The voltage is measured in the unchanged system between two selected contact points. The point to which the COM cable leads is used as the reference point for the displayed polarity of the voltage value. COM is preferred connection for ground. If you swap the measuring cables, the same numerical value is displayed for the voltage, only with the opposite sign.

Common errors:

a) If the fused current input socket was accidentally used for an intended voltage measurement, the internal fuse of the device usually blows , which often goes unnoticed for a long time!

b) If AC voltage is incorrectly measured in the DC voltage range, the display is always close to zero.

Current measurement

To measure the current , the line in which the current to be measured flows must be disconnected. This is expediently done at a connection point.

If the multimeter fuse has blown , zero is always displayed for the current!

Resistance measurement

For resistance measurement , the element must be separated from the system by at least one connection , otherwise incorrect measurements will occur.

Special measurement problems

Measurement of very high resistances (> 10 kΩ): Do not bridge the measurement connections with your fingers during the measurement, because the parallel body resistance falsifies the result.

Measurement of very small resistances (<10 Ω): Before the measurement, bring the ends of the measuring cables together and read the value (lies in the range of 0 .0.5 Ω). The correction value determined in this way must then be subtracted from each measured value. If the measuring cables are exchanged, the correction value must be determined again.

Measurement of the smallest resistances (<10 mΩ): A known current is sent through the resistor - if possible - and the voltage drop is measured directly (!) At the resistor. The value is calculated as R = U / I. For illustration: measuring current 1A, measured 1 mV results in R = 1 mV / 1 A = 1 mΩ.

Fidgeting display or implausible values with digital multimeters

Digital measuring devices are usually more nimble than analog pointer instruments. This can lead to short interference pulses (e.g. from the ignition) being detected and causing the display values to jitter. For this reason, the measuring lines should generally be routed as far away as possible from cables and ignition equipment. With DC voltage measurements, a ballast as shown below can help in stubborn cases. Interfering frequencies> 30 Hz are thus suppressed. If this is not enough, the capacitor can be increased (e.g. 10 times the value). The larger the capacitor, the more effective the suppression of voltage fluctuations, but the slower the response of the display.

DC voltage filter as ballast

Such malfunctions do not normally occur in vehicles with an intact electrical system. It is therefore important not to be satisfied with eliminating the symptoms, but to look for the causes of the interfering impulses. The following are to be examined: spark plug connector (internal flashovers), ignition capacitor (ineffective), collector (grooves, nicks, scaling) or slip rings (breakouts), regulator contacts (burn-off), loose contacts / broken cables, fuse contacts (corrosion).

A DC generator and 6 V electrical system

A.1 Field-regulated DC alternator for 6 V vehicle electrical system

A.1.1 Checking the winding resistances

Before the LiMa is tested with the motor running, the winding and insulation resistances should be checked (for setpoints, see Table A.1-3). Since the measurement of very small or very large resistance values harbors particular risk of error, the instructions in Section V.3 must be observed.

If slightly higher values occur with certain rotor positions, sanding the copper lamellas with 500 grit sandpaper often helps.

If the rotor continues to turn, it is possible that the multimeter display goes "crazy". This has to do with the fact that the residual magnetism induced when the rotor moves a voltage that confuses the resistance measurement. The reading is only to be taken when the rotor is at a standstill!

The actual insulation resistances are mostly over 20 MΩ.

Fig. A.1-1: 6 V / 10 A / 60 W DC generator of an ES150, exciter series resistor R has been removed (yellow symbol R)

Test object	Measurement conditions	Resistance measurement between	LiMa 6 V / 60 W.	LiMa *) 6 V / 30 W.
Rotor- winding	Loosen the copper wire of the minus carbon Loosen the D + cable Loosen the D + side connection from R. Slowly turn the rotor 360 ° during the measurement so that all segments of the collector are checked.	D + and loosened copper braid of the minus coal	(0.2 ± 0.2) Ω	(0.8 ± 0.2) Ω
Rotor- isolation	- ditto -	D + and ground	> 1 MΩ	> 1 MΩ
Field- winding	DF + sided Loosen connection from R. Loosen the DF cable Loosen the DF winding end from the ground	DF + and DF-	(1.7 ± 0.3) Ω	(2.6 ± 0.3) Ω
Field- isolation	- ditto -	DF + and ground	> 1 MΩ	> 1 MΩ
R.	Both connections solve from R.		(4.5 ± 0.5) Ω	unavailable
R insulation	- ditto -	any Connector and metal body	> 1 MΩ	unavailable

Table A.1-3: Setpoints for winding and insulation resistances

*) LiMa 6 V / 30 W for RT125 / 0-2

Definition of "plus or minus regulation" for vehicles with a negative pole on the chassis according to [5]

In the plus-regulated LiMa , the plus- side field winding connection (DF +) is led to the controller connection (DF).

The minus-side field winding connection (DF-) is connected to ground (D-) (see Figure A.1-2a). If an excitation field series resistor R is available, it is connected between D + and DF.

With the minus-regulated LiMa , the minus- side field winding connection (DF-) is led to the controller connection (DF).

The positive-side field winding connection (DF +) is connected to D + (see Figure A.1-2b). If an excitation field series resistor R is available, it is connected between DF and D-.

A.1-2: Alternator, electrical block diagram

DF- negative end of the field winding,

DF + positive end of excitation field winding

DF controller connection for field winding

R series resistor for field winding

(not applicable when using electronic controllers)

D + positive collector carbon brush (short: plus carbon)

D- negative collector carbon brush (short: minus carbon) = ground

The excitation field series resistor R is often designed as an external resistor (see Fig. A.3-1), but it can also be used in the excitation field winding itself (e.g. RT125 / 3 series partially) or in the electro-mechanical controller (e.g. IFA RT 125 ) be integrated.

Plus and minus rules are of equal importance , they have neither advantages nor disadvantages in relation to the other type of circuit. There are also no differences in terms of the magnetic or electrical polarization of the LiMa.

If the winding ends of the excitation field winding are accessible, a minus-regulated LiMa is created by reconnecting the field winding connections to a plus-regulated one and vice versa. If it is a field winding in which the excitation field series resistor is integrated (feature: 3 connections emerge from the stator), it is no longer effective after the conversion, so that an external resistor must be provided.

If the control type is specified, this has an impact on the design of the controller. The plus regulator must "send" a positive current into the DF + connection so that the generator voltage increases, the minus regulator must "pull out" a positive current from D- to achieve the same effect. As a visual comparison, imagine a tube with a suction pump connected to the left in the first attempt and a pressure pump to the right in the second attempt. The liquid flows through the tube in the same direction in both cases, but the pumps are of different construction.

All MZ two-stroke engines are plus-regulated, the exceptions are the BK350 and the last series ETZs (around 1990) with a regulator circuit.

With the RT125 / 3 there are irritations as to whether the plus or minus control was originally intended or whether a changeover occurred during series production. Separate controller types would then be required for plus and minus regulations. So far, only plus-regulated systems could be found in RT125 / 3 vehicles that had been checked in practice and were apparently in their original condition.

It can therefore be assumed with a very high degree of probability that the RT125 / 3 is generally plus-regulated .

The cause of this confusion is possibly an error in the circuit diagram of the RT125 / 3, which is in the original operating instructions and which is also found in other publications. The error can even be found in the diagram on the inside of the bobbin case cover. The exciter field series resistor is incorrectly drawn in parallel to the field winding, which makes no electrical sense.

A.1.2 Alternators - function test

If the resistance measurements according to A.1.1 do not show any irregularities, the LiMa can be tested with the engine running. All cables (D +, DF +) leading to the controller must be disconnected and secured beforehand. In this test, a fault in the rotor (e.g. winding short) can be detected if the voltage at D + does not reach the orientation value mentioned above.

Fig. A.1-4: LiMa test circuit with external excitation

After connecting the battery, the 6 V lamp lights up and a current of around 1.8 A is impressed into the field winding. The engine is now started normally (on battery ignition) and the voltmeter is observed. If the speed is higher than idle, the generated DC voltage must quickly rise to 10 ... 12 V with an intact LiMa and the 12 V lamp connected as a load lights up. If the 18 W incandescent lamp is removed, the 60 W lamp goes out regardless of the speed.

Caution: Do not increase the equivalent speed beyond 12 V, the light bulb can burn out!

To be on the safe side, if all previous measurements and tests were successful, the self-excitation can still be checked. To do this, all lamps are disconnected when the motor is at a standstill and a wire bridge is inserted between DF + and D +. The engine will start again. A voltage of 12 ... 15 V must be generated at a slightly increased speed. Incidentally, this situation corresponds to the push-on position of the ignition light switch. However, since the controller is not effective in this test, it should last a maximum of 10 s in order not to overload the field winding.

Self-excitation requires a sufficiently large residual magnetism in the iron core of the windings. If this has been lost or there is a magnetic reversal of polarity (e.g. if the LiMa has been stored in the earth's magnetic field for a long time), it can be assumed that sufficient residual magnetism will remain after the function test described above has been carried out.

The magnetization or magnetic correct polarity can, however, also be brought about a little more aggressively by bringing the positive terminal of the battery (unsecured!) Into contact with D + for a moment (0.1 s).

A.2 Electromechanical controller (E / M, 6V)

A.2.1 Mechanical adjustment

The structure of the electromechanical voltage regulator was kept almost unchanged from the first RT in 1950 to the 12 V systems of the ETZ series of the 1990s. Deviations can be found in the details, e.g. in the mechanical design of the bending elements.

Figure A.2-1: Designation of the contacts and setting elements on the electromechanical

Controller, older on the left, newer on the right

In the literature [1] and [2] you can find different adjustment measures. Based on this information, sensible orientation values have been set in Figure A.2-2 (blue entries).

Control of the mobility of the contact anchor plates

First it is checked whether the contact tongues can be pressed easily up to the core without the angled lower ends of the contact anchor plates sitting on the core foot. In the relaxed state, a dimension of 0.5 mm is given in [1]. If nothing sticks, nothing should be changed in the current distance, even if the value is not exactly 0.5 mm!

Setting the controller contact (left side)

The setting of the magnetic gap (1 mm) and the controller contact spacing (0.4 mm) takes place in one step, as both fixed contacts can be moved after loosening the upper cylinder head screws. The magnet gap (1 mm) is set by moving the left fixed contact and the contact distance (0.4 mm) by moving the right fixed contact.

Fig. A.2-2: Orientation values for the distances to be set

Image A.2-3: Determination of the gap width with existing aluminum rivets

in the contact anchor plate

This attitude requires skill and patience. And it has to be right in the end when the cylinder head screws are tightened again! If you hit the target values within ± 0.1 mm, you can be satisfied.

Setting the reverse current contact (right side)

Magnet gap (0.8 mm) and contact distance (0.4 mm) are also set simultaneously after loosening the corresponding cylinder head screws. The contact distance (0.4 mm) can be set with the left fixed contact. Here, too, a setting accuracy of ± 0.1 mm should be aimed for.

Note

As soon as mechanical changes are made to the controller, changes to the electrical setting values are to be expected, so that subsequent electrical adjustment is absolutely necessary!

A.2.2 Electrical adjustment

The connection sequence applies to older controllers (see Fig. A.2-1) with screw connections:

51 DF D + / 61

The plug contact version has the following sequence:

DF D + 61 51

where D + and 61 have separate contact lugs, but are connected to one another. The ground contact is on the base plate of both controller versions.

Fig. A.2-4:

(a) Functional diagram of the electromechanical regulator for the 6V / 60W generator.

(b) Regulator of the 6 V / 30 W LiMa for the RT125 / 0-2 with integrated field winding series resistor

Preliminary test of the controller with the help of resistance measurements

(unused connections remain open)

The resistance of the voltage _coil R _SSP was determined from our own measurements on several copies of 6 V / 60 W regulators with different production dates. The last measured coil resistance with 10 Ω was marked 3/76 and the first with 20 Ω was marked 4.80. The conversion must therefore have taken place between 1977 ... 1980.

The reason for this could be a desired reduction in the wire cross-section of the voltage coil. In addition to saving copper, this also reduced the controller's power consumption from around 5 W by 50% to 2.5 W.

Before the measurement, the contacts must be cleaned with a strip of hard, transparent drawing paper (parchment), otherwise the small contact resistances of 0.2 Ω and less are hardly achievable!

element	Resistance Measurement between the connections	condition	Value for Regulator of 6V / 60W- LiMa	Value for Regulator of 6V / 30W LiMa RT125 / 0 ... 2
Voltage coil	D + / 61 and mass		R SSP	R SSP (10 ± 0.5) Ω
Controller contact	D + / 61 and DF	Rest position Middle position pressed on	0 ... 0.2 Ω infinite R SSP	0 ... 0.2 Ω R V (7 ± 0.5) Ω R SSP // R V (4 ± 0.5) Ω
Controller contact	Dimensions and DF	Rest position Middle position pressed on	R SSP infinite 0 ... 0.2 Ω	R SSP (10 ± 0.5) Ω R SSP + R V (17 ± 0.5) Ω 0 ... 0.2 Ω
Reverse current contact	D + and 51	Rest position pressed on	infinite 0 ... 0.2 Ω	infinite 0 ... 0.2 Ω

Table A.2-5: Setpoints for resistance measurements on the controller.

R _SSP : voltage _{coil resistance} up to the end of the 1970s: (10 ± 0.5) Ω from the beginning of the 1980s: (21.5 ± 1)  Ω,

R _V : field winding series resistor

Notes on measuring the RT125 / 0-2 controller relay when it is removed

On the rear side (inside the coil box) the lead out connection corresponds to terminal 51. On the front side of the regulator relay (facing outwards in the coil box) there are 3 wire connections. DF is the first connection that leads to the middle contact spring of the controller contact. DF must be connected to the second connection coming out of the winding! Ground comes as a third connection from the inner fixed regulator contact. D + is to be connected to the bottom of the metallic core of the coil former. If the controller is measured in the coil box on the vehicle, all cables leading to the outside must be loosened from the screw terminals.

Electrical adjustment of the controller

Confusing facts from the literature [2]

The information on the electrical adjustment of the 6 V regulator in the literature [2] (see Table A.2-6) is hardly practicable; the problem is explained below. The recommended procedure is shown on the next page.

The information from [2] is given in Table A.2-6. Compliance with the specified speeds can at best be estimated for the TS and older models that do not have a tachometer.

Pick-up voltage reverse current contact	6.5V ... 6.9V
Drop-out voltage reverse current contact	5.4V ... 6.2V

on-board voltage to be set for N = 1800 ... 2200 min-1 and 10 A load	6.2V ... 6.8V	A.
on-board voltage to be set for N = 4000 min-1 for continuous daylight operation	6.8 V ... 7.2 V	B.

Load case A: low beam (40 W) + rear light (5 W) + stop light (18 W) = 63 W,

gives a total of 10 A at 6.3 V and disconnected battery

Load case B: Not further defined

Table A.2-6: Voltage values for electrical adjustment taken from the

Literature [2]

The usual load in solo daylight mode is 40 W (low beam) + 5 W (rear light), which is around 8 A. In addition, there is an average of 2 A for the ignition coil, which adds up to 10 A. Turn signals and stop light are consumers that usually only work for a short time. When fully charged, the intact battery takes up almost no more charging current. It can be seen from this that the two load cases A and B hardly differ at all.

For the daylight operation prescribed today, 6.8 ... 7.2 V should be set according to the table. With a permitted 7.2 V, however, at 25 ° C one would already be at the gassing limit of the lead-acid battery (see Section V.2). If you consider that the setting accuracy of the mechanical regulator is often worse than 0.1 V and that changes also occur due to wear and tear of the contacts during operation, the battery could endure if you just hit the upper limit of the permitted range would meet.

In addition, the table allows the reverse current contact to be adjusted to 6.9 V in extreme cases, but the on-board voltage comes to a maximum of 6.8 V. According to the table, this would be permitted, but fatal, since the LiMa would then never be connected to the on-board network or the battery.

For all of the reasons mentioned above, sensible setting values that have proven themselves in practice are therefore suggested in the following work steps .

Adjustment and preparation procedure

The sequence of the work steps must be strictly adhered to.

1) Adjustment of the pull-in voltage of the reverse current contact

2) Check the dropout voltage of the reverse current contact

3) Voltage adjustment of the regulator contact

4) Checking the charging voltage in the vehicle under normal operating conditions

Before setting, clean the contacts with a strip of hard, transparent drawing paper or parchment! In stubborn cases, sandpaper with a grain size of 500 or finer should be used.

1) Inrush voltage of the reverse current contact

The reverse current contact must close when the generator voltage exceeds the typical open circuit voltage of the battery (6.3 V). This results in a meaningful target area for the

Pull-in voltage of the reverse current contact: (6.4 V  ± 0.1) V .

The voltage of the controllable voltage source is slowly and continuously increased starting from zero (measuring circuit see Fig. A.2-7) until the contact picks up (= lamp lights up). If the tension is too low , the associated bending element must be bent outwards in order to increase the restoring force of the contact restoring spring or vice versa.

Fig. A.2-7: Circuit for voltage adjustment

of the reverse current contact

Since the bending elements made of aluminum or brass become brittle after a few rough bends and can break off, you should work very carefully and avoid unnecessary bends.

If several switching attempts are carried out under the same conditions, the reproducibility of the switching point will usually be poor. Experience has shown that fluctuations of ± 0.1 ... ± 0.2 V are typical. The reasons for this are: wear of the contacts, variable residual magnetism in the core, changes in properties due to the relay heating up during the adjustment procedure.

2) Check the dropout voltage of the reverse current contact

In order to control the drop-out voltage, the reverse current contact is first closed by increasing the voltage (= lamp lights up), whereby the voltage must be increased further until the contact anchor plate or the aluminum rivets are completely in contact with the core. Only now is the voltage slowly and continuously reduced until the reverse current contact drops out (= lamp goes out). According to the information

from [2] (see Tab. A.2-6) the permissible range for the drop-out voltage is 5.4 ... 6.2 V. The voltage should not be lower than 5.4 V, as the battery is then with Idle speed increasingly against the LiMa begins to work. However, nothing can be adjusted if the dropout voltage should be lower than 5.4 V.

3) Voltage adjustment of the regulator contact

The measuring circuit according to Figure A.2-8 only differs from the previous one in that the test lamp is now connected to terminal DF. The voltage of the controllable DC voltage source is increased slowly and continuously from zero. We observe that the return current contact is first tightened (click), and when it is increased further, the armature plate of the return current contact hits the core (click). Both processes (click - click) can also take place almost at the same time.

Fig. A.2-8: Circuit for voltage adjustment of the regulator contact

As the voltage increases, the brightness of the incandescent lamp increases. If the voltage is so high that the regulator contact anchor plate is attracted, the regulator contact opens and the bulb goes out.

Then we increase the voltage by a further 0.3 ... 0.5 V and observe how the regulator contact moves evenly beyond the central position in the direction of the inner fixed contact. However, if the regulator contact armature is suddenly pulled to the core shortly after it has been lifted off, the two fixed contacts must be pushed outwards by a few tenths of a millimeter in parallel. To do this, loosen the screws originally secured with paint. After this correction, the anchor plate distance to the core is slightly larger than specified in the mechanical presetting. Then check that the contact moves evenly beyond the central position.

Now the switching point of the controller contact is delicately limited by increasing or decreasing the voltage several times (light bulb alternately "on" <-> "off"), then measured and recorded. In an optimum charging voltage of 6,9V plus a derivative of 0.2V (voltage drops via cable, securing, etc.) as a set value 7.1 V sought.

If the voltage is too low , the associated bending element of the controller contact (see Figure A.2-1) must be bent outwards in order to increase the restoring force of the contact restoring spring. If the tension is too high, bend the bending element inwards .

You should definitely get an impression of the extraordinary sensitivity of the setting before re-bending by tucking a piece of paper under the return spring and observing the change in the switching voltage. Experience has shown that this manipulation leads to value changes of up to +0.5 V depending on the thickness of the paper strip.

Since the bending elements are made of aluminum and become brittle and break off after repeated bending, you should absolutely avoid unnecessary bending.

The setting of the RT125 / 0-2 controller for the 6 V / 30 W LiMa is possible with the specified circuit. Because of the integrated series resistor, the light bulb does not go out at the switching point, but only becomes slightly darker. The difference in brightness at the switching point is small and therefore more difficult to perceive.

4) Checking the charging voltage in the vehicle under normal operating conditions

Before checking the vehicle, make sure that the cabling is OK and the contacts (especially on the fuses) are in good condition in order to keep voltage drops to a minimum.

The controller is installed in the vehicle and the engine is started. "Usual operating conditions" mean here: Slightly increased speed compared to idling (corresponding to about 2000 ... 3000min ^-1 ) and low beam on. Now the voltage is measured directly at the battery terminals. Under normal ambient temperature conditions (15 ° C ... 25 ° C) this is 6.9 V.the desired setting value. Since a few amps of load current (headlights, taillights, ignition, battery charge) flow through the controller's current coil, the control voltage systematically decreases by 0.3 ... 0.5 V compared to the original setting after step 3. The correction increases higher tension values can easily be achieved by placing strips of paper underneath the contact spring, which prevents the bending elements from bending.

Electromechanical controllers change their properties over longer periods of operation. It is therefore advisable to check the charging voltage on the battery every year as described above and to adjust it if necessary.

Electromechanical regulators do not regulate load fluctuations ideally, so that, for example, when the low beam is switched off, the charging voltage jumps up by up to half a volt.

Anyone who has set the regulator according to the above regulation, but afterwards thinks that they have to do something good for the battery by driving without the low beam, will achieve exactly the opposite. The higher charging voltage will very likely exceed the gassing limit of the battery and reduce its service life or even lead to destruction!

A.3 Electronic controller (6 V)

A.3.1 Removal of the regulator resistor

If the electromechanical controller is replaced by an electronic one, it is necessary to remove the field winding series resistor. Figure A.1-1 shows the LiMa already with the regulator resistor removed.

It is also possible to leave the series resistor in the LiMa and simply put it out of operation. This has the advantage that when upgrading to an electromechanical controller, all parts are available and you only have to reconnect. The two connecting wires of the series resistor are screwed together under the fastening screw of the winding body foot (earth) (see Figure A.3-1).

Fig. A.3-1: Deactivated field winding series resistor

(both connections clamped under fastening)

If the controller in the coil box of the RT125 / 0-2 is replaced by an electronic version, no measures are required, as the field winding series resistor is integrated in the controller relay and is therefore removed when it is removed. With the RT125 / 3 , the series resistor is located in the LiMa as usual and must be removed or rendered ineffective.

A.3.2 Electronic controller - function test

Most electronic controllers (analog principle) can be tested for function with the same test circuit as was used for the electromechanical in the removed (or "disconnected") state.

Fig. A.3-2: Circuit for the function test

of the electronic controller

When the voltage at D + / 61 is increased, the brightness of the lamp initially increases to the same extent. When the cut-off voltage is reached and exceeded, the incandescent lamp goes out. In principle, this can be done "gently", that is in the range of a few tens of mV.

The switching point is therefore determined at medium brightness of the lamp. Since most electronic regulators use a semiconductor diode as a non-return valve, the value of the cut-off voltage at the switching point must be equal to the amount of the diode forward voltage (Si-pn diodes: 0.8 V ... 1.0 V, Schottky diodes 0.4 V ... 0.5 V) higher than 6.9 V.

Cut-off voltages of 7.3 V ... 8.0 V are therefore classified as unsuspicious.

Fig. A.3-3: Circuit for testing the non-return valve

In case (a), the incandescent lamp must remain dark. The reverse current displayed by the multimeter should be well below 1 mA (typically µA range).

If one takes 1mA as the value for the diode reverse current in the worst case , then calculated over a month this would cause a creeping discharge of the battery of 30 x 24 hx 1 mA = 0.72 Ah and would just be acceptable.

In case (b) the incandescent lamp lights up and approx. 2 A flow. In this case, the multimeter shows the diode forward voltage of the reverse current diode , which is approx. 0.8 ... 1.0 V (for Schottky diodes 0.4 .. .0.5 V).

Due to the differently designed products, when using an electronic controller, it is very important to check the voltage on the battery under real load and operating conditions in the vehicle after the successful function test.

Usually nothing can be set on the electronic controller, so that you can only find out whether the battery charging voltage is acceptable or not (see section V.2.3 "Checking the operating conditions in the vehicle electrical system").

In a pinch, however, which can be Controller voltage by inserting a diode at 51 / B + to a diode forward voltage lower . When attaching the diode, however, its power consumption of up to 10 W must be taken into account.

A.4 Contact ignition system (6 V)

A.4.1 Overview

This section is about checking all components of the ignition circuit for proper function. Instructions for setting the breaker ignition can be found in Chapter V.7. The ignition system includes the breaker contact actuated by the crankshaft cam, the ignition capacitor, ignition coil, ignition cable, spark plug connector and spark plug. Experience has shown that faults in the ignition system are the most common cause of engine failure. If only one of the heavily used components fails, the entire system fails.

A.4.2 Contact, ignition capacitor

In order to include the lead to the ignition coil when checking the breaker contact, the cable at terminal 1 is disconnected from the ignition coil for the duration of the measurement and the resistance to ground is measured at the end of the cable.

(a) Contact closed: <0.1  Ω * *) Definitely measuring tips

(b) Contact open: > 1 M Ω * note in chapter V.3

It usually takes a while until a correct resistance value is displayed for measurement (b), as the ignition capacitor lying parallel to the contact has to be reloaded by the measuring device.

If the values do not come true, the following causes (among others!) May be present:

(a) resistance greater than 0 , 1  Ω : corroded breaker contacts, dirty or worn out, cable or clamping points (see Section V.1..) is defective or unreliable

(b) Resistance much less than 1 M Ω : Cable insulation defective, capacitor has plate connection

Figure A.4-1: Problem areas on the contact spring (A) and contact riveting (B)

A more precise assessment of the closed interrupter contact is possible if the voltage drop between the connection lug of the capacitor and ground is measured. When the ignition is switched on, a contact current of approx. 4 A flows in 6 V systems, and 2.7 A in 12 V systems. The voltage drop above the original

MZ contacts is typically around 90 mV or 60 mV. If it is significantly larger, the 3 measures outlined below can possibly bring about an improvement:

1) Smooth out eroded contacts with a contact file.

The burnished wire spring and the two contacts A (see Fig. A.4-1) cause a considerable proportion.

2) Carefully file the wire spring eyelet under the M3 nut until it is bright or add an M3 tooth lock washer.

3) Rivet the rivets on the upper contact. For this purpose, the lower contact plate is placed on a metal plate and a punch is placed on the flat head B. With a few blows, the upper contact is slightly mushroomed and the contact resistance is reduced.

The result can be checked by measuring the voltage drop again. If no improvements are possible, the contact should be exchanged.

The capacitor can stand on its own when removed

· Isolation (resistance> 1 M Ω ) and

· Capacity (0.22 µF + 20% / -10%) can be checked.

If the capacitor values are OK at room temperature, this does not necessarily mean that correct functioning is guaranteed even if the temperature in the motor housing is increased. Failures that only occur at engine operating temperature and "heal" again when cold are possible.

In the case of defective ignition capacitors (before 1990), for example, when heated to 100 ° C, a sharp drop in insulation resistance (<< 1 M Ω) with a simultaneous increase in capacitance (up to 5 times the nominal value), which led to misfires. To heat up the capacitor for a heat measurement, immerse it about 1 cm deep for about 5 minutes in boiling water and measure resistance ( > 1 M Ω) and capacitance (0.22 µF + 30% / -20%) immediately after Remove. It is important to ensure that the potting gap on the housing and on the contact does not come into contact with water, as it easily penetrates as it cools down.

A.4.3 Ignition coil

The function of the ignition coil is a transformer with a primary (index 1) and secondary coil (index 2). Every technical coil is determined by its inductance L (in H) and its winding resistance (in Ω ). The parameters of the equivalent circuit of the 6V ignition coil were determined and averaged experimentally on several specimens.

A.4-2: Equivalent circuit of a 6V ignition coil

Although there is a series connection of resistance and inductance between terminals (1) and (15) as well as between (15) and (K), the digital multimeter only records the resistance because it is measured with direct current. The multimeter does not "see" the inductance when measuring resistance, just like when measuring winding resistances in the LiMa.

The nominal values for winding and insulation resistances are listed in Table A.4-3. In any case, short circuits and ground circuits as well as winding breaks can be found.

element	Measurement between	resistance	Approximate values for RT125 / 0-3
Ohmic resistance of the primary coil	(1) and (15)	(1.5 ± 0.2)  Ω	1.3  Ω
Ohmic resistance the secondary coil	(15) and K	(7.5 ± 1) kΩ	3.3 kΩ
Insulation resistance	(1) and housing such as (15) and housing such as (K) and housing	> 1 M Ω each

Table A.4-3: Winding and insulation resistances of the 6V ignition coil

Poor contact between the ends of the windings (1) and (15) is a fault that sometimes only appears when heated up due to sporadic misfiring. In order to improve the contact, the contact caps of the ignition coil are unscrewed and their inner surfaces are made bare with a fiberglass brush. The winding ends are very carefully scratched (if the wire breaks!) Until the copper shine can be seen (Fig. A.4-4). To counteract further corrosion, a little Vaseline grease can be put under the caps before putting them on.

Figure A.4-4: Dismantled contact cap on the ignition coil

If the resistance values are within the tolerance, this does not necessarily mean that the ignition coil is OK. Internal voltage flashovers can already occur in the cold state if the properties of the insulation material have changed.

Similar to the ignition capacitor, thermal problems often lurk in the ignition coil, which remain hidden when measuring on the workbench when it is cold.

The reasons for this are thermal changes in the winding and insulation properties as well as chemical effects after penetration of moisture. In the latter case, electrochemical elements can even form (copper winding - water - aluminum housing). On a defective specimen, after heating, a direct voltage of up to 1000mV was found between the open terminals (1) / (15) and the aluminum housing. If the coils are faultless, the values are well below 10mV.

Good statements can be made with the test setup described below

Win picture A.4-4. The circuit corresponds to a minimum ignition circuit set up outside the vehicle (see Figure A.4-6), but instead of the spark plug, an adjustable spark gap (ignition voltage tester) is used. The voltage source (lead battery) is selected according to the nominal voltage of the ignition coil to be tested. Since higher ignition voltages are generated during the test than is the case in normal operation, higher primary voltages (up to 500V) can also occur at terminal (1). Instead of the usual ignition capacitor, a more voltage-resistant (0.22µF / 2000V) must be used.

In order to achieve reproducible, bounce-free switching processes, the use of a mercury switch (Hg switch, Hg tilt switch) is required. All components of the test site are currently (2014) still available in relevant motorcycle accessories and electronics stores. However, it is to be expected that mercury switches will disappear from the range in the future, as has already happened with mercury thermometers. Experienced electronics engineers can, however, also replace the Hg switch with a voltage-proof transistor ignition.

Fig. A.4-5: Circuit and practical structure for testing ignition coils

Safety note: In particular, people with impaired health are strictly discouraged from operating the test station. Accidental sparkover on any part of the body can be life-threatening.

The electrode spacing of the spark gap is always changed when the battery is disconnected. 6 V ignition coils have a maximum spark length of 8 ... 10mm, 12 V ignition coils 10 ... 15mm. High humidity has a strong influence on the spark length that can be achieved. In dry air, a breakdown field strength of 3kV / mm is expected. 10mm spark length means 30kV voltage!

The ignition coil is heated up by keeping the Hg switch permanently closed. The heating process is carefully monitored. Excessive heating will destroy the ignition coil. After 3 to 5 minutes, a temperature has usually already been reached that just barely allows the housing to be touched. The spark test is now repeated with the ignition coil warmed up. Based on previous experience, a reduction in the maximum spark length of 20% can be regarded as normal. If the reduction is greater, it must be assumed that the heated ignition coil in the vehicle can cause ignition problems.

A.4.4 Ignition cable, spark plug cap and spark plug

Ignition cable

In the case of the ignition cable, lengthy measurements will be dispensed with and if mechanical wear of the copper core at its ends or visible corrosion can be seen, it will be replaced. If it should nevertheless be checked: The copper core has a very small resistance, which, within the scope of our measurement accuracy, would have to be specified as (0.0 + 0.1)  Ω . However, there are also cores made of resistance material, whereby the cable is then supposed to take over the function of the interference suppression resistor. The cable resistances in conventional lengths are then in the order in which the values for suppression resistors are, therefore, 1 k Ω to several 10 k Ω. These cables work well with our MZs if the ignition system has no weaknesses elsewhere. If you are unsure, you can make no mistake about replacing such a cable with one with a normal copper core.

Spark plug connector

There is usually an interference suppression resistor (1 k Ω ... 10 k Ω ) in the plug connector . The value is usually noted as an indication on the connector, although there are also connectors without resistance, i.e. with zero Ω .

When measuring the continuity from the cable-side connector input to the plug-side contact, this value must be verifiable to ± 20%. Infinite resistance means that there is an interruption, the plug must be replaced, even if it strangely still works, because the interruption may be overcome by a flashover inside.

If the connector is sheathed in metal, the insulation resistance to the sheet metal sheath must be well above 1 M Ω .

Persistent moisture at the connection points between ignition cable - ignition coil and ignition cable - spark plug connector often leads to ignition failure. As is well known, this happens suddenly in heavy rain or creeping in with morning pew. Tightly fitting and non-porous sleeve sleeves protect against this, but also keep moisture that has penetrated in for longer. The sheet metal jacket of the candle holder is also a moisture collector in this regard. If the "originality" does not suffer and nobody complains about radio interference, you should remove the sheet metal covering of the plug connector with suitable pliers.

spark plug

The candle is almost impossible to get at by measuring it. Only the traditional method of subjectively assessing the spark at the electrodes according to its strength helps here. It has to be strong and bluish-white, accompanied by a clearly audible crack. One speaks of the crisp spark ...

However, it must be taken into account that there are high temperatures and high pressure in the cylinder, which can mean that the candle that has passed the roadside visual test nevertheless reacts with "spark silence" in the cylinder. Only a (really !!!) fresh candle will help. And if it should then work satisfactorily, the most important action is still to come, namely to actually throw away the defective candle! Honestly, I didn't always do it consistently, and what was the result? That at some point - all previous history is forgotten - after years you will screw in the same cucumber again and bring yourself to the brink of despair through your own fault.

The value of the interference suppression resistor (s) in the ignition circuit

can vary within wide limits without adversely affecting the proper function, whereby an overall intact ignition system is assumed.

If the candle is weakening and moisture has crept into the ignition cable and the battery is at the end of it, increasing the interference suppression resistor from 0 to 100 kΩ may tip the scales, which in no way means that the above thesis is wrong.

It even sparks with a blade of grass in the "high resistance area" instead of the ignition cable and also with a suppressed candle (NGK BR ...) and a suppression resistor in the plug! The participants at the forum meeting in Sosa 2008 were able to see this for themselves with their own eyes and ears.

Anyone who has the experience that it ignites "noticeably" better without resistance should not be talked out of this for the Buddha's or whose will. It is important that you have personally gained a positive experience and are happy with it from now on. And zero point zero ohms are not wrong either!

Minimum ignition circuit

If there is no ignition spark or if the ignition is unreliable, it is worth setting up a "minimum ignition circuit" as shown in Figure A.4-6. Only the absolutely necessary components are used in order to exclude possible errors in the wiring of the machine as well as short circuits, line breaks, fuse problems and the ignition light switch.

Figure A.4-6: Structure of a minimum ignition circuit

As long as this structure does not work, there is little point in looking for the fault elsewhere. If it works, however, please note that the engine can only be stopped by disconnecting the battery!

The ignition circuit - hardness test

The best way to check whether an ignition system is "overall intact" is with a spark gap. The breakdown limit for dry air is around 3 kV per millimeter. A U-shaped plastic plate and a plastic clothes peg are used to fix the ignition cable that has been detached from the spark plug connector. The copper core must be flush with the cut surface of the ignition cable insulation, if this is not the case, the ignition cable must be shortened by 2 ... 3 mm with a "fresh" cut. The counter electrode made of solid copper wire is screwed directly onto the upper plug contact with an M4 nut (see Figure A.4-5).

We start with 2mm clearance and get the engine running. If the spark gap does not break through, something is wrong. It should be possible to increase the distance up to 5 mm (corresponding to 15 kV) without the motor running unevenly. The test ETZ150 was still running at a distance of 10.5 mm!

Fig. A.4-5: Estimation of the maximum ignition voltage

with a test spark gap

Safety note: In particular, people with health problems are strictly discouraged from performing the test in this way. With modern, high-energy ignition systems, an accidental sparkover on a part of the body can be life-threatening.

B Three-phase generator and 12 V electrical system

B.1 Field-regulated three-phase alternator for 12 V vehicle electrical system

B.1.1 Checking the winding resistances

Fig. B.1-1: Block diagram of the 14V / 15A three-phase LiMa and voltage

a LiMa phase in relation to crankshaft rotation

The stator and rotor windings are designed in such a way that 4 full sine periods are generated on each of the phases U, V and W per crankshaft revolution (see diagram in Figure B.1-1). This relationship is important for the signal generation of electronic tachometers, which are clamped to a phase line of the LiMa.

A very simple check of the windings of the rotor and stator was described in [7 [ . Apart from a light bulb 12V / 21W, no further measuring or testing equipment is required. This method may be used in vehicles with conventional plus-regulating electromechanical or electronic controllers, but not in on-board power systems with minus-regulating regulator circuit L9480 (see also Section B.4.3).

a) Switch the test lamp between terminal 51 on the controller (= positive pole of the battery) and the DF cable disconnected from the controller, test lamp lights up (compared to step b)) with reduced brightness. If not, possible causes of error: Si defective, DF cable interrupted, carbon brushes defective, field (rotor) winding interrupted.

b) Connect the test lamp between 51 on the controller and ground. Test lamp shines brighter than in step a). If not, there may be a short to ground in the DF cable or in the rotor.

c) Disconnect cables U, V, W from the rectifier. Switch the test lamp between 51 and one after the other against the cable ends U, V, W. Lamp stays dark. If not, there is a short to ground in the stator winding or in the supply lines.

d) Connect cable U to 51 on the controller. Switch the test lamp between V and earth and between W and earth, the test lamp lights up. If not, the stator winding or the supply lines U, V, W have an interruption.

More precise information can be obtained by measuring the resistance directly on the alternator (for setpoints, see Table B.1-2). These should generally be carried out before the LiMa is tested with the engine running according to B.1.2.

element	Measurement conditions	Measurement between	resistance
Three-phase windings	Cable at U, V, W removed	U and V V and W W and U	0.32 Ω each  according to [7]
isolation	dito	U and ground V and ground W and mass	each > 1 M Ω
Field winding (Rotor)	Cable removed from DF- and DF + Slowly turn the rotor 360 ° during the measurement	DF + and DF-	(4.2 ± 0.3)  Ω according to [2]
Field isolation	dito	DF and mass	> 1 M Ω

Table B.1-2: Winding and insulation resistances of the 14V / 15A three-phase LiMa

Since the measurement of very small or very large resistance values harbors particular risk of error, the instructions in Section V.3 must be observed.

A test object measured 4.5 Ω for the field winding (rotor) . Depending on the state of wear, everything between 4… 5 Ω should be okay. The insulation resistance was generally over 20 MΩ.

B.1.2 Alternators - function test

The cables U, V, W and DF + disconnected from the LiMa must be secured against unintentional contact.

As shown in Figure B.1-3, three test lamps are connected directly to the LiMa plug-in contacts U, V, W. The use of three 60 W headlight bulbs is only necessary if the maximum power output of the LiMa is to be achieved. Otherwise, 3 x 21 W is sufficient for the test. However, three lamps are essential.

Either the on-board battery or an external power supply unit (at least 2 A) can be used as a 12 V fixed voltage source to generate the excitation current.

Fig. B.1-3: LiMa test circuit with external excitation

As soon as the 21 W lamp is connected to the positive pole of the 12 V on-board battery, it starts to light up. The applied excitation current is about 1.3 A.

The engine is now started normally with the battery ignition and the engine speed slowly increased from idle speed until the AC voltage on the multimeter

(Select AC range!) Has reached 12 V ~. All 3 lamps in strings U, V and W must shine equally brightly, around 180 W are converted. If the 21 W incandescent lamp is removed, the 3 load replacement lamps go out regardless of the speed.

Caution: If the speed is increased further, the voltage rises above 12 V ~ and there is a risk that the light bulbs will burn out!

Image B.1-4: Practical implementation of the load equivalent circuit with three

H4 lamps screwed onto a copper bar

B.1.3 The field winding fuse 2A "slow"

The field winding of the 14V / 15A three-phase LiMa is protected with a 2 A fuse. In normal operation, the field current remains mostly below 2 A. Depending on the field winding resistance (4.3 ± 0.3  Ω ) and on-board voltage (max. 14.2 V), peak values of 3.4 ± 0.2 A are possible (e.g. with low speed and full load).

The 2 A fuse with the property "slow" will usually withstand these short-term overloads. However, if a fault occurs (e.g. a diode on the rectifier plate has broken through, overload due to a severely discharged battery, short circuit, etc.), which continuously demands the maximum field current, the fuse will blow after a long time and protect the LiMa from further damage.

However, it is obvious that in this context “good” (<2A) and “bad” (> 2A) are close to one another. Even the wrong characteristic ("nimble") would probably blow the fuse the first time it was exceeded. On the other hand, a fuse value> 2 A would make the intended protective mechanism absolutely ineffective. If the 2 A fuse blows frequently, the LiMa, rectifier, battery and on-board network should definitely be subjected to a thorough check. But it is also conceivable that the fuses used were not sufficiently “slow”.

Due to the high operational reliability of the rectifier

plate (200 V version), the protection could also be omitted entirely. To be on the safe side, a 100 µF / 63 V capacitor should be provided as shown in Figure B.4-2.
B.2 rectifier block

B.2.1 Circuit

Function of the rectifier block

The diodes D1 to D6 form a standard three-phase, three-phase rectifier bridge , the AC voltage inputs of which are the 3 generator phases U, V, W and the DC voltage output of which is the D + connection.

When installed, D + is looped over the controller and the fuse and thus directly connected to the positive pole of the battery. In addition to the task of AC voltage rectification, the diodes D1, D3, D5 must also serve as reverse current diodes, i.e. even if the generator voltage is zero at standstill, the battery cannot reverse discharge via the three three-phase windings, because D1, D3, D5 then block.

However, this is also the reason that the controller does not have any useful information about the current generator voltage at D +, because the battery voltage is always present there, even when the engine is not running.

Image B.2-1: Rectifier block (left) and equivalent circuit (right)

In order to obtain a rectified voltage that corresponds to the current generator voltage, an additional rectifier circuit consisting of D7, D8 and D9 leading to connection 61 is required. There the speed- and load-dependent, rectified generator voltage can be tapped, the size of which is decisive for the controller for controlling the excitation current.

As a result, it is not the voltage at D + that is the controlled variable, but the voltage at connection 61. This leads to effects such that a load or temperature-related voltage change at diodes D1, 3, 5 from diode trio D7, 8, 9 at 61 hardly "noticed" and therefore not corrected. This fact must also be taken into account when troubleshooting. The controller is not always defective if the voltage values on the battery are not correct. The rectifier must always be included in the error analysis.

Dielectric strength of the diodes

The first rectifier modules up to 1986 [2] contained type SY170 / 1 and SY171 / 1 diodes with only 100V blocking voltage, so that voltage peaks in the on-board network had to be suppressed with an additional 2.5 µF capacitor.

The more voltage-resistant variant can be recognized by the sticker "UR = 200 V". If it has dissolved, you can recognize them by the 200 V components SY170 / 2 and SY171 / 2. Unfortunately, both variants have the same spare part number, namely 8046.2-300. If the plate is changed, it must be ensured that the capacitor is present in the 100 variant. In the case of the 200 V rectifier module, the capacitor can be removed, but it can also be left without affecting its function.

It is easily possible to replace a defective rectifier plate with a modern 3-phase rectifier block for 15 A or more and with a blocking voltage> 200 V. The auxiliary bridge D7, 8, 9 must then also be implemented, whereby its current load can be set to be significantly lower (approx. 5 A).

B.2.2 Function test

The function test of the rectifier block when it is not connected is limited to the individual test of all rectifier diodes. Either you use the diode test function of the multimeter or you create a continuity tester with simple means, as shown in Figure B.2-2.

(a) (b)

Image B.2-2: (a) Test in forward direction (lamp lights up), display: forward voltage

(b) Test in reverse direction (lamp does not light up), display: reverse current

	A node	K atode
D1	U	D +
D2	Dimensions	U
D3	V	D +
D4	Dimensions	V
D5	W.	D +
D6	Dimensions	W.
D7	U	61
D8	V	61
D9	W.	61

Table B.2-3: Allocation of the diode connections

In principle, transmission (lamp must light) and blocking behavior (lamp remains completely dark) must be checked.

The forward voltage (= forward voltage) of each diode is (0.85 ± 0.15) V at approx. 1 A forward current (slightly dependent on the battery condition and the power consumption of the bulb used). The reverse current must be well below 1 mA, typically in the µA range.

B.3 Electromechanical controller (12V)

B.3.1 Mechanical adjustment

The mechanical adjustment of the 12 V controller differs in the following points from that of the 6 V controller described in Section A.2.1:

The so-called current limiting contact is located at the place of the reverse current contact .

According to [2], the contact distances are

Current limiting contact 1.5 mm

Regulator contact 0.3 mm

B.3.2 Electrical adjustment

As already explained in section B.2.1 on the rectifier block, the controller input (61) and the on-board power supply (51 / D +) must be galvanically isolated from each other in the 12 V three-phase system, since the Battery voltage is present.

Fig. B.3-1: Electrical function diagram of the electromechanical controller.

The main current path from D + to 51 "winds" around the controller core with a large cross-section only a few times. If the current in the main current path is too high or if there is a short circuit, the few windings cause the current limiter contact to open. If the current limiter opens, the field winding can no longer be supplied with the maximum voltage from 61, but at most via the field winding series resistor. This at least prevents extreme overloading of the LiMa in the event of a fault (Fig. B.3-1).

The coil-resistor combination parallel to the voltage winding is probably a device for temperature compensation of the controller.

Connection sequence of the electromechanical 12 V regulator:

Ground DF 61 D + 51 ground

Preliminary test of the controller with the help of resistance measurements

(unused connections remain open)

Before the measurement, the contacts must be cleaned with a strip of hard, transparent drawing paper (parchment), otherwise the small contact resistances of 0.4 Ω and less cannot be detected!

element	Measurement between	condition	resistance
Voltage coil	61 and mass		R SSP (18 ± 2) Ω
Current limiter contact and Controller contact together	DF and 61	Rest position Current limit open Controller contact in Middle position	0 ... 0.4 Ω R V (8.5 ± 2) Ω R V (8.5 ± 2) Ω
Controller contact	DF and mass	pressed on Middle position Rest position	0 ... 0.2 Ω R V + R SSP (26.5 ± 4) Ω R SSP (18 ± 2) Ω
Current winding	D + and 51		0 ... 0.2 Ω

Table B.3-2: Resistance values on the 12 V regulator

Electrical adjustment of the controller

In contrast to the 6 V controller, general operating parameters are given for the 12 V controller in [2] that can only be checked when installed and with the engine running (see Table B.3-3).

As with the 6 V system, concerns about the upper limit of the on-board voltage of 14.6 V (= gassing limit of the battery at 25 ° C) must be reported, especially since the voltage information relates to an unspecified point in the on-board network, i.e. possibly can also refer directly to the battery terminals.

Regulated voltage when the LiMa is loaded with 3 A. over the entire speed range	13.8 ... 14.6 V.
Maximum load voltage when the LiMa is loaded with 15 A, N> 3800 min ^-1	13.0 ... 13.5 V.
Start of current control *)	11.5 ... 14.0 A

*) the current limiter contact starts to work

Table B.3-3: Information on electrical adjustment from [2]

The following instructions enable the controller to be checked when it has been dismantled, so that a statement on the function is possible regardless of the engine running and the rest of the electrical system.

Fig. B.3-4: Circuit for voltage adjustment

of the controller contact or function test

Voltage adjustment of the regulator contact

The voltage of the controllable DC voltage source is increased slowly and continuously, the brightness of the incandescent lamp increasing to the same extent. If the voltage is increased further above 12 V, the lamp suddenly decreases its brightness a little. When the voltage is reduced, the point at which the light bulb becomes brighter is reached again. This switching point, which can be easily limited by carefully varying the voltage, should be around 14.0 V. To determine the value, an optimal charging voltage of 13.8 V for the battery and a lead value of 0.2 V for voltage drops across cables and fuses were taken into account.

If the tension is too low , the bending element must be bent outwards in order to increase the return force of the contact return spring.

If the tension is too high, bend the bending element inwards .

The on-board voltage value must be checked or corrected after the controller has been installed (see Section V.2.3) in order to allow for an adaptation to the special conditions. In addition to the difficult to predict voltage drops in the on-board network, there is also the fact that the on-board voltage (51) and the regulator input voltage (61) are not identical and can differ by a few tenths of a volt (see explanations in the section on rectifier block B.2.1).

Control of the current limit

The test described below is actually not advisable because the effort involved in checking the current limiting function hardly justifies the benefits. Nevertheless, a proposal should be made for checking outside the on-board network. For a better understanding, the complete internal circuit of the controller has been shown (Fig. B.3-5).

Fig. B.3-5: Circuit for checking the current limiter contact

An external 12 V starter or car battery is best used for the test because a very high current is required for a short time. About the way:

61 -> current limiter contact -> regulator contact -> DF

the test lamp receives 12 V operating voltage and lights up.

At 51, the circuit is briefly closed (caution, high power consumption!) Via a 0.7 Ω resistor. About 17 A flows from D + to 51 through the regulator. The maximum value of the current at which the limiter contact opens (see Table B.3-3) is 14 A. Accordingly, it should open with certainty at 17 A test current, which can be seen from the reduced brightness of the test lamp, as it is no longer now receives voltage directly, but via the internal regulator resistor. As a precaution, it should be checked that the loss of brightness is not caused by a voltage drop in the battery when the current is high. To do this, briefly contact the positive pole of the battery with the 0.7 Ω resistor, whereby no loss of brightness should be discernible.

Low resistances for high loads in short-term operation can be provisionally made from copper wire (see section V.1.1 "Cable resistances").

20 m Cu line of 0.5 mm ² results in about 0.7  Ω . A test duration of 1 s or less is sufficient to determine the decrease in brightness of the test lamp.

Caution: The wire heats up instantly, so that the insulation is destroyed over a longer period of time and there is an acute risk of fire.

B.4 Electronic controller (12V)

B.4.1 Replacement of electromechanical by electronic plus regulator

Image B.4-0: Comparison of the integration of mechanical (a) and electronic controllers with (b) or without (c) separate connections for (D +) and (51)

In the instructions for the installation of commercially available electronic controllers, it is always required that the field winding series resistor must be removed.

With the 12 V three-phase systems, this resistance is not in the LiMa, as with

the 6 V systems, but is located under the base plate of the electromechanical controller. If this controller is removed, the series resistor is automatically removed and no further measures are required.

Does the electronic controller to be used have no separate connections

for D + and 51 (= B +) on, then D + from the rectifier plate is directly connected to battery positive

to be connected (Fig. B.4-0).

12 V three-phase systems with electromechanical controllers are plus-regulated . The electronic replacement regulator must therefore also be a plus regulator .

B.4.2 Function test for electronic (plus) controller

Fig. B.4-1: Circuit for the function test

Electronic (plus) controllers can be checked for function with the circuit specified above (Fig. B.4-1) when they have been removed (or "disconnected"). This applies both to commercially available, universally applicable electronic controllers and to self-made solutions. When the voltage at 61 is increased, the brightness of the lamp increases to the same extent. When the cut-off voltage is reached and exceeded, the incandescent lamp goes out in the range of a few tens of mV.

The switching point for the reduction is determined when the lamp is at medium brightness. It should correspond to the optimal charging voltage of 13.8V. If you factor in a voltage drop of a few tenths of a volt across the lines and the fuse, the cut-off voltage can also be higher by this amount. Cut-off voltages of 13.8 V ... 14.0 V are therefore optimal.

However, as with almost all commercial electronic controllers, there are no controls for the voltage at the regulator itself. Emergency is an increase in the voltage by a prescreening ( ³ possible 3-amperes) diode at the (61) of the regulator. He then quasi "sees" a measurement voltage reduced by the forward voltage of the diode, which leads to an increase in the charging voltage at the output of the rectifier plate (D + = 51 = B +) by the same amount.

The voltage in the main circuit can be reduced by inserting a ( ³ 15 ampere) diode in front of the main fuse. Since the entire LiMa current flows through the diode, a power consumption of up to 15 W must be taken into account when installing.

B.4.3 rectifier / Electronic (minus - ) controller in the last 2T models

In the course of further development, the controller circuit (One Chip Car Alternator Regulator) L9480 (manufacturer:

ST.SGS-Thomson Microelectronics) is used (Fig. B.4-2), which works as a minus regulator. A detailed description of the properties of the switching regulator L9480 can be found in Appendix Z.4.

Fig. B.4-2 : Circuit of the rectifier-regulator assembly

Schottky diodes were used as rectifier diodes which, due to their low forward voltage, allow a low power loss and thus a better degree of efficiency compared to conventional Si-pn diodes .

The input signal for the electronic tachometer (DZM) is picked up from one of the three-phase connections U, V, W. For the function it does not matter which one is used.

Thanks for information from torbiaz, paule56, TS-Jens (mz-forum.com)

Left : Conventional variant with right: Electronic rectifier /

electromechanical controller controller assembly with electronic

Tachometer (DZM)

Fig. B.4-3 : Integration of the electronic rectifier / regulator assembly into the on-board network of the ETZ.

Just like the DZM line, the LKL line (charge control light) is a “hot” connection, as it is routed unsecured through the vehicle. In the event of a short to ground, not only are the rectifier diodes endangered, but there is also an acute risk of fire, as the full LiMa power is behind it. We recommend installing a flying fuse (500 mA) close to the rectifier / regulator.

In a first variant, the rectifier / regulator assembly was arranged under the bench instead of the rectifier plate (Fig. B.4-4).

In the later version, the rectifier controller board, which is soldered to the winding connections U, V, W, is located in the LiMa housing (Fig. B.4-5).

Image B.4-4: Rectifier plate with regulator

circuit L 9489 (Photo: Ysengrin, mz-forum.com)

Image B.4-5:

Rectifier regulator board on the LiMa LiMa, G / R board unsoldered and

(Photos: paule56, mz-forum.com) dismantled

B.4.4 Function test of rectifier / electronic (minus) controller

The rectifier plate with the regulator circuit under the seat or the rectifier regulator board on the LiMa must be removed from the vehicle for the test. The circuit board on the LiMa must be carefully unsoldered from the wire connections U, V, W so that the conductor tracks and winding ends are not damaged. Since the individual rectifier diodes should not be unsoldered from the regulator circuit, the function test is more complex than with the standard rectifier board (see B.2.2); 4 measuring circuits (a) ... (d) are required for this.

If irregularities occur during the diode tests, the controller circuit still in the circuit must be included in the investigation as a possible source of error!

	A node	K atode
D1	U	D +
D3	V	D +
D5	W.	D +
D7	U	61 / DF +
D8	V	61 / DF +
D9	W.	61 / DF +
D2	Dimensions	U
D4	Dimensions	V
D6	Dimensions	W.

Figure and Table B.4-6: Testing in the forward direction (a)

In test step (a), all diodes are tested in the direction of flow. The forward voltage of the Schottky diodes used is 0.4 ... 0.5 V. If voltage values close to zero volts or greater than 1 V are displayed, it is very likely that the corresponding diodes have failed.

	A node	K atode
D1	U	D +
D3	V	D +
D5	W.	D +

Figure and Table B.4-7: Testing in the blocking direction (b)

D1, D3, D5 can be tested in test step (b) in the known standard circuit in the reverse direction. Normally the reverse current is below 1mA, typically it is only a few µA or even less. The additional connection after connection (61) or ground in test steps (c) and (d) is required to divert the operating current of the regulator circuit. If the connection is omitted, the multimeter shows the operating current of the L9480 regulator circuit (approx. 20 mA) instead of the reverse current of the diodes.

	A node	K atode
D2	Dimensions	U
D4	Dimensions	V
D6	Dimensions	W.

Figure and Table B.4-8: Testing in the blocking direction (c)

	A node	K atode
D7	U	61 / DF +
D8	V	61 / DF +
D9	W.	61 / DF +

Figure and Table B.4-9: Testing in the blocking direction (d)

For the controller test (circuit L9480), set up the circuit as shown in Figure B.4-10. The procedure is identical to that described in Section B.4.2.

Image B.4-10: Circuit for function test
B.5 Ignition system (12V)

B.5.1 Contact ignition system

The contact ignition system for 12V vehicle electrical systems does not differ in principle from the 6 V system. In this respect, the sections

A.4.2 Contact, ignition capacitor

A.4.3 Ignition coil

A.4.4 Ignition cable, connector and plug

V.7. The setting of the breaker ignition

with regard to fault diagnosis, testing and maintenance. The ignition coil for 12V only has different resistance values. Unfortunately, only a single coil was available to limit these parameters, so the measured values do not necessarily have to be typical (see Table B.5-1).

element	Measurement between	resistance
Ohmic resistance of the primary coil	(1) and (15)	(4.5 ± 0.5)  Ω
Ohmic resistance the secondary coil	(15) and K	(8.5 ± 1) kΩ
Insulation resistance	(1) and housing such as (15) and housing such as K and housing	> 1 M Ω each

Table B.5-1: Winding and insulation resistances of the 12 V ignition coil

B.5.2 Electronic ignition system with Hall sender

(1) "Hermsdorfer MZ ignition"

The electronic ignition system consists of the transmitter unit attached to the crankshaft with the Hall element (= sensor sensitive to magnetic fields) and the remote signal processing unit.

Fig. B.5-2: Encoder unit with removed Fig. B.5-3: Equipment side of the

menem permanent ring magnet signal processing unit

(Photo: Voodoomaster, mz-forum.com)

Fig. B.5-4: Encoder unit Fig. B.5-5: Signal processing unit

Function test of the encoder unit

First the connection cable is checked for continuity from the blade terminal to the board solder point. The function of the Zener diode is then tested as shown in Fig. B.5-6; the voltage between 15g and 31g must be 4.75… 5.25 V. If it is above 7 V, the Zener diode is defective. Since it is soldered onto the conductor track from above (see Figure B.5-2), it can be replaced, but problematic because of the solid potting compound. It is easier to leave the defective diode and add a 5.1 VZ diode on the board of the signal processing unit (between (15g) and (31g)).

If the Zener diode was defective, it may be that the sensor circuit has already been destroyed due to the impermissibly high voltage at pins 3 and 4, which can be found out with the help of the switching test described below. If a more voltage-resistant circuit B462 (operating voltage 4.75 ... 18 V) is used, the 5 VZ diode is still required because the internal input pin 3a maximum of 5.5 V may be applied to both circuit variants. If the ring magnet is turned, the 12 V LED lights up over an angle of rotation of 180 ° if the encoder is intact and remains dark for the following 180 °. This means that the transmitter function can be verified at least statically. However, after a successful static test, it is unlikely that malfunctions will occur in dynamic operation at higher speeds.

Fig. B.5-6: Circuit for the function test of the encoder unit

Fig. B.5-7: Circuit for the function test of the signal processing unit

Function test of the signal processing unit

In the test circuit shown in Figure B.5-7, the 12 V / 21 W bulb is used to simulate the load on the ignition coil. If the transmitter unit switches "on", the potential at (1) is drawn down to approx. 1 V residual voltage against ground and the light bulb lights up. This is achieved by connecting the terminal (7) to ground (31g or 31) with a wire bridge. If (7) is open again, the light bulb must not light up. If the incandescent lamp lights up continuously or remains dark, there is a fault in the signal processing unit of the electronic ignition system.
(2) "PVL / MZ ignition"

Hall sensor and signal processing unit of the PVL / MZ ignition are in

a red or black cast function block directly on the LiMa (Fig. B.5-8).

Image B.5-8: Electronic PVL / MZ ignition (Photo: Welu, mz-forum.com)

Fig. B.5-9: Circuit of the electronic PVL / MZ ignition

The PVL ignition can be statically tested in the removed state analogous to the test circuit shown in Figure B.5-7. On the input side, however, actuation takes place by moving a thin sheet of iron past the sensor as a magnetic screen. If the unit is intact, a switching process occurs (lamp on / off). As with the Hermsdorfer ignition described above, a residual voltage of approx. 1 V remains at terminal (1) in the on state.

A disproportionately high expenditure of special electronic measuring technology is required to prove frequently described, probably thermally caused failures, so that it cannot be discussed here.

Thanks to IFArista, mz-forum.com for providing the analysis sample C permanent magnet 12V three-phase

generator (Rotax)

C.1 Three-phase generator - function test

As with the field-regulated three-phase generator, the stator contains the voltage induction coils. Instead of the excitation field coil, however, a rotating permanent magnet - similar to a bicycle dynamo - is arranged. The generator voltage can therefore not be influenced via the excitation field as with the field-regulated three-phase generator (Chapter B). The faster the rotor turns, the greater the generator voltage becomes. We are used to it in the same way from conventional bicycle dynamos.

The stator winding and rotor are designed in such a way that 6 full sine periods are generated on each of the phases U, V and W per crankshaft revolution (see diagram in Figure C.1-1). This relationship is important for the signal generation of electronic tachometers, which are clamped to a phase line of the LiMa.

Fig. C.1-1: Block diagram of the 12 V / 190 W permanent magnet three-phase LiMa and

Voltage of a LiMa phase in relation to crankshaft rotation

If a fault is suspected in the LiMa, the winding resistances should first be checked in order to detect winding shorts / interruptions or insulation problems. In [4], different resistances or ranges are specified for the individual three-phase windings, which were only partially confirmed in an exemplary test measurement on an intact vehicle. The resistance of all three strands was uniformly 0.7 Ω when measured on a vehicle 

element	Measurement conditions	Measurement between	resistance
Three-phase windings	Cable from Connector strip deducted	white and orange white green green orange	0.6-0.9 [4], own measurement 0.7  Ω 0.54-0.8  Ω [4], own measurement 0.7  Ω 0.8-1.6  Ω [4], own measurement 0.7  Ω
isolation	dito	white and ground green and ground orange and ground	> 1 M Ω, typically over 20 M Ω

Table C.1-2: Winding and insulation resistances of the Rotax LiMa

If the resistance measurement (see Table C.1-2) does not reveal any abnormalities, the LiMa can be tested with an equivalent load (Figure B.1-4). For this purpose, three 60 W headlight lamps are connected to the three-phase connections U, V, W (or cable colors white, green, orange) as shown in Fig. C.1-3, the controller remains disconnected. It would be safer to use 24 V lamps, if available, as the alternating voltage already reaches 12 ... 14 V at idle speed. The speed must therefore never be increased! The headlight lamps must shine brightly.

Fig. C.1-3: LiMa test circuit

If power resistors 12 Ω / ≥60 W are used instead of incandescent lamps, the speed can be briefly increased to 3000 min ^-1 . The alternating voltage reaches a value of approx. 27 V ~ (measure at U, V, W one after the other), whereby a power of approx. 180 W is drawn from the LiMa .

C.2 Rectifier / regulator block - function test

The Rotax regulator is a block that contains the usual three-phase bridge rectifier (circuit similar to Fig. B.2-1, but without diodes D7-D9) and 3 thyristor switches (for a detailed circuit see Appendix Z.2). When the target DC voltage is reached at the output (black cable), the individual (yellow) three-phase connections are short-circuited to ground by thyristors for the duration of one or more voltage half-waves, so that the output voltage remains at the target value and cannot increase any further.

Fig. C.2-1: Connections on the rectifier / controller block. The three-phase connections (yellow) are basically interchangeable and are therefore not differentiated on the controller block

The test of the rectifier function is completely analogous to the test of the rectifier block in section B.2. The conduction (a) and blocking behavior (b) of the individual internal rectifier diodes must be checked as shown in Figure C.2-3.

A node	K atode
U	B +
Dimensions	U
V	B +
Dimensions	V
W.	B +
Dimensions	W.

Fig. C.2-3: Diode test Table C.2-2:

(a) Test in the forward direction (lamp lights up), connection diagram

Display: forward voltage

(b) test in reverse direction (lamp does not light up),

Display: reverse current

The forward voltage (= forward voltage) is (0.85  ± 0.1) V at approx. 1 A forward current (depending on the battery status and the power consumption of the light bulb). The reverse current must be well below 1 mA, typically in the µA range.

The function of the thyristor switch can be checked by connecting a controllable DC voltage source to the three-phase current connections via a 12 V / 10 W light bulb as shown in Fig. If the voltage of the source is increased slowly, you will find a switching point at around 14 V at which the lamp suddenly starts to glow and at the same time the voltage display at B + jumps to zero. If the voltage of the source is now reduced again, the lamp continues to glow, but becomes darker as the source voltage is reduced. A new switching attempt can only be started after the lamp has been briefly disconnected from the three-phase connection.

Fig. C.2-4: Test of the internal thyristor switching function

Switching points determined in practice at B + for three controller copies at U, V, W were: 13.95 V-13.89 V-13.96 V; 13.96V-13.97V-13.96V; 13.96V-14.23V-13.96V

Based on the example measurements, you can expect values in the range of 13.7 ... 14.4 V with a perfect controller.

C.3 Electronic tachometer (eDZM)

The input of the eDZM with the type designation 12 P VCC 12 is connected to one of the three three-phase phases (U, V, W) coming from the LiMa. According to the repair instructions [8], p. 38, that phase must be selected for the connection which “is live in every operating state of the charging system”. To find out, the engine should run, the battery should be fully charged and no other loads should be switched on. All three phases are probed one after the other with an alternating voltmeter. At the phase "which carries voltage, the signal cable comes green".

The above procedure is functionally incomprehensible. In practice, all three strings U, V, W carry voltage that is more or less subject to the phase control of the switching regulator. It will never be the case that only one phase is live and the remaining two are completely switched to zero. At best, you will find a phase whose tension is greater than that of the other two, because it is not at all or less often compared to the other two. If you select this, however, it is not guaranteed that with longer journeys and higher engine speeds it will also be cut in or cut away over more or less periods. As is well known, this leads to incorrect display values or chaotic fluctuations in the display.

That is why there were changes about a year after the start of series production. The eDZM of the type 12 P VCC 2, which has been used since 1992, is now connected to the blue wire from the ignition sensor to the ignition box. This provides a stable input signal with speed information for the eDZM. Both eDZM types are not interchangeable! The 12 P VCC 2 can, however, be built into the older Rotax models, whereby its input has to be connected to the blue wire from the ignition box mentioned above.

More information on the functioning of the electronic DZM used by MZ can be found in Section V.6.

C.4 Electronic ignition (CDI, Nippondenso)

The ignition of the Rotax engine 504E works according to the CDI process ( C ondensor D ischarge I gnition = capacitor discharge ignition). The capacitor contained in the amplifier box is charged by two charging coils located in the stator, the lower one in Figure C.4-1 being effective at low speeds and the upper one at higher speeds. The ignition point is determined by two transmitter coils, with the external sensor realizing an ignition angle of 3 ° before TDC at low speeds and the internal sensor at high speeds up to 29 ° before TDC.

If the stop switch is operated, the internal capacitor is short-circuited and the ignition spark is instantly eliminated.

Fig. C.4-1: Connections of the CDI ignition box (amplifier box, Nippondenso 070000-0780)

Fig. C.4-2: Pin assignment on the amplifier box

According to the repair manual for the Rotax motor [4] p. 45, testing the amplifier box is limited to measuring the resistance between all completely disconnected cable connections. If input elements are "shot", you will find out with them. However, this method is not a 100% functional test.

The resistance matrix given in [4] is flawed in that plus and minus were swapped in the matrix on page 45. On the other hand, a contemporary ohmmeter is required (the motor went into series production around 1980) that works with an external test voltage of> 2 V in order to be able to test diodes in the direction of flow. This was usually the case with the pointer instruments of the time without electronics. Nowadays, modern multimeters often work with voltages below 0.5 V at the measuring sockets, so that there are displays that do not have to coincide with those in the matrix specified there.

Suitable test equipment with which the test can still be carried out nowadays are

a) Multimeters that deliver a voltage of at least +2 V to the measuring sockets in the resistance measuring range (20 kΩ) or in the "Diode test" operating mode (if available) (checking by direct voltage measurement with a second multimeter is possible) or

b) the test circuit according to Figure C.4-2

When testing with a test lamp, however, it must not happen that the connections of the amplifier box inadvertently come into direct and simultaneous contact with the plus and minus pole of the battery, as this would destroy internal components. Test lamp outputs greater than 2 W can also be harmful.

Fig. C.4-2: Test equipment for testing the amplifier box and the associated test matrix

If the amplifier box is unplugged, the winding resistances of the charging, transmitter and ignition coils can also be checked in order to determine breaks in the windings or short circuits to ground (see [4] p. 44). According to Fig. C.4-1, it must be ensured that the ground connection of the external transmitter coil is not connected to the other ground connections when it is disconnected.

The cable colors pink - orange - brown are not always easy to distinguish, especially when they are dirty. It is therefore imperative to clarify this before taking measurements.

The internal circuitry and function of the amplifier box are explained in more detail in Appendix Z.3.34.

V Miscellaneous

V.1 Cable connections

V.1.1 Cable resistance and voltage drop

The resistance between the two end connection points is decisive for assessing the quality of a cable connection. Since these resistances are usually less than 100 m Ω , an exact direct measurement with simple digital multimeters in the resistance measuring range is hardly possible.

Copper cross-section	length-related resistance	Voltage drop for 1m and 10A current
6 mm ^2	2.9 mΩ / m	30 mV
4 mm ^2	4.4 mΩ / m	40 mV
2.5mm ^2	7.0 mΩ / m	70 mV
1.5mm ^2	11.7 mΩ / m	120 mV
1 mm ^2	17.5 mΩ / m	180 mV
0.75mm ^2	23.3 mΩ / m	230 mV
0.5mm ^2	35.0 mΩ / m	350 mV

Table V.1-1: Cable resistances and voltage drops for different cross-sections

It is therefore more practical to measure the voltage drop across the cable connection when the test current is known, since even simple digital multimeters offer a sufficiently accurate voltage measurement in the mV range.

Fig. V.1-2: Measuring circuit for cable voltage drop

The measuring circuit according to Figure V.1-2 is variable with regard to the impressed current, which is determined by the battery voltage and the power consumption of the incandescent lamp. In this example, a 6 V / 18 W incandescent lamp and a 6 V battery are used, which gives about 3 A test current through the cable, which is precisely determined with the multimeter before the actual measurement. The voltage drop is now tapped with the multimeter within the two feed points (in the example cable clamps with eyes) so that the voltage drops are not recorded directly at the feed points.

Measurement example:

Cross section of the cable to be tested 0.75 mm ² , length 1.3 m

Resistance per meter according to table V.1-1: 23.3 m Ω / m.

Resistance for 1.3 m cable length: 23.3 mΩ / m * 1.3 m = 30.3 m Ω

Expected voltage drop for 3 A: U = I * R = 3 A * 30.3 mΩ = 91 mV

Assuming the practicable test accuracy of 10% , a measured value in the range of 80 ... 100 mV would be expected. If the voltage drop exceeds the maximum value by more than 50%, there is very likely a cable fault.

V.1.2 Voltage drops in the vehicle electrical system

Voltage drops in the 6 V electrical system with conventional breaker ignition are particularly critical; it is worthwhile to identify neuralgic points. Intermittent ignition at idle speed and / or when the headlight is switched on are usually a sign that the voltage effective on the ignition coil is significantly lower than the terminal voltage on the battery. Causes are partial voltage drops via cable and plug connections, fuses, ignition light switches and the breaker contact.

The systematic investigation is based on the schematic circuit shown in Fig. V.1-3. The procedure outlined below can also be transferred to 12 V systems or other areas of the vehicle electrical system.

Before the measurement it is ensured that

that the measuring points A to L are freely accessible,

that the lower cup contact is closed and

that the battery is OK and fully charged.

It is advisable to measure in the 2 V DC voltage measuring range of the digital multimeter, since the voltages are only a few tenths of a volt.

(a) (b)

Fig. V.1-3: Complete ignition circuit for determining the partial voltage drops

(Explanation: H: base plate of the U-contact, G: contact lug on the capacitor)

Starting with the plus side (a) of the circuit according to Fig. V.1-3, the "V" socket of the digital multimeter is firmly connected to the plus pole of the battery via the plus measuring cable. The measuring points A to E are scanned one after the other with the minus measuring line ("COM" socket). The test tip is placed safely and firmly on the respective measuring point. The ignition and the light are switched on briefly for the measurement . Since the battery is loaded with around 10 A at this moment (headlights, taillights, ignition coil), 1 ... 2 s must be sufficient for reading. The measured value is entered according to the example in Table V.1-4. The measurements on the minus side (b) according to Fig. V.1-3 are carried out analogously. Finally, the differential voltages are calculated in the table.

In order to obtain reproducible results, the battery voltage should remain as constant as possible during the measurement (check with a multimeter). The battery voltage usually recovers in short pauses between measurements, and recharges if necessary.

If the differential voltages are more than 50% above the typical values given in Table V.1-4, improvements must be made to the corresponding elements (check cables and cable connections as well as plug-in forces, clean contacts, maintain U-contact, check fuses and fuse contacts) .

Improvements can generally be achieved by increasing the cross-section of the cable connections. It is also advantageous to solder the cable connections (flat connectors, eyelets) or to re-solder existing crimp connections in the entire circuit A to L. The ignition light switch has several contact lugs (15/54), exchanging the slots may lead to an improvement. The conversion from torpedo to flat fuses is recommended.

The sum E + F (voltage loss over all) indicates how much lower the voltage applied to the ignition coil is compared to the terminal voltage on the battery; a value below 800 mV = 0.8 V should be aimed for.

Measuring Point	Voltage in mV		Diff. Voltage in mV	Responsible element
		A.	24	Cable connection from battery positive to the plus fuse Si2
A.	24
		BA	95	Plus fuse Si2 including fuse contacts
B.	119
		CB	73	Cable connection from Si2 to the ignition light switch (30)
C.	192
		DC	111	Ignition light switch between (30) and (15/54)
D.	303
		ED	55	Cable connection from the ignition light switch (15/54) to the ignition coil (15)
E.	358
				E + F = voltage loss over everything: 640 mV
F.	292
		FG	31	Cable connection from U-contact to the ignition coil (1)
G	261
		GH	90	U contact
H	171
		HK	52	Ground cable from Si1 to the ground connection in the alternator
K	119
		KL	95	Minus fuse Si1 including fuse contacts
L.	24
		L.	24	Cable connection from battery minus to the minus fuse Si1

Table V.1-4: Exemplary measurement protocol with averaged measurement values of three

Vehicles (ES150, ES150 / 1, ES175 / 2). The vehicles were with

Flat car fuses and some larger ones with cables

Cross-section equipped.

The differential voltages can also be measured directly, as shown in the example in Fig. V.1-5. This method is recommended if the success of improvements to a certain element is to be tracked by measurement.

Fig. V.1-5: Differential voltage drop across the ignition light switch

V.2 accumulator (lead battery)

V.2.1 Characteristic values and properties

The battery is the most sensitive, capricious and most difficult to see through creature in the vehicle, which is why this section on its properties is also quite long. If you are only interested in subjecting your battery to a function test, you can confidently jump to Section V.2.2.

Since the lead acid battery is still most frequently used in the vehicle sector, all information and tests refer to it. Much of this, however, can also be transferred to other battery systems - eg NiCd - in the same way.

An accumulator , known colloquially as a battery, stores electrical energy in a chemical way. The lead battery contains sulfuric acid as an electrolyte. In contrast to the primary battery, it can be repeatedly discharged and charged.

Its most important parameters are nominal voltage [V] , nominal capacity [Ah] and internal resistance [m Ω ].

The prefix "nominal" means that the properties are intended for the design, in contrast to this, "voltage" and "capacity" denote the current, available values that a particular specimen has at the moment, i.e. depending on the state of charge, Temperature or age.

The term capacity refers to the battery capacity for electrical charge. The battery capacity thus indicates in an idealized way the maximum current [A] that can be drawn from the battery over how many hours [h].

Example: With 6 Ah it is ideally 1 A over 6 h or 0.6 A over 10 h or 2 A over 3 h etc., the product of current and time always results in 6 Ah.

When the battery is intact, the voltage drops to a constant value a few hours after the end of the charging process, the no-load voltage . If, for example, the vehicle was parked overnight, the no-load voltage can be measured the next day before starting the journey. The open circuit voltage and other significant voltage values for lead batteries can be found in Table V.2-1. With fresh batteries, the value for the open circuit voltage can be up to 5% higher than specified.

The (maximum) charging voltage must always be sufficiently below the gassing limit . As can be seen from Table V.2-1, the margin of around 4% is very small.

The maximum charging voltage at room temperature (25 ° C) is 6.9 V or 13.8 V for the 6 V or 12 V lead-acid battery.

It is wrong to assume that a full battery could be charged further by increasing the charging voltage above 6.9 V or 13.8 V. Because the battery plates have already been completely chemically converted, the flowing current only leads to more intense electrolytic splitting (gassing). Exceeding the maximum charging voltage - true to the motto "a lot helps a lot" - is often the cause of an abnormal shortening of the battery life .

Values for 25 ° C	single cell	6 V battery	12 V battery
Gassing limit	2.40V	7.20V	14.4V
maximum charging voltage	2.30V	6.90 V.	13.8V
Rest tension, for example	2.10 V	6.30 V	12.6V
Minimum voltage	1.87V	5.60V	11.2V
Deep discharge limit	1.75V	5.25V	10.5V

Table V.2-1: Important voltage values of the lead battery at room temperature [3]

With the currently available rechargeable batteries, a very weak gas development (quiescent gassing) can sometimes be observed even in idle mode. If the battery has remained unchanged for a long time and if you tilt it to the side, you can see or hear gas bubbles rising. The reasons for this phenomenon are unclear, but it is obviously not of concern. Above the gassing limit, an electrolytic cleavage reaction with very violent gas development (oxygen + hydrogen) occurs compared to the weak quiescent gassing.

The internal resistance indicates how much the battery voltage drops when power is drawn. The smaller the internal resistance, the lower the terminal voltage drop.

Example: A battery has a current terminal voltage of 6.47 V. Its internal resistance wasspecifiedas 45 mΩ. When connecting a consumer that draws 10 A, the terminal voltage of the battery drops by 45mΩ · 10 A = 450 mV, ie the terminal voltage is only 6.02 V.

In order to conserve the battery, the charging current in A should not be greater than 1/10 of the Ah number , whereby this should be interpreted as a rough rule of thumb with leeway. At a

11 Ah battery, for example, the charging current should not exceed 1.1 A. This rule can only be complied with with a convenient charger that has a current limiting function, but not in the vehicle. If the battery is heavily discharged, the regulator in our MZ will take care of it a waste, because it is a constant voltage regulator . If the battery is heavily discharged (eg "overnight stay" with parking light), the charging voltage (see table V.2-1) is effective from the first moment and a multiple of the recommended maximum charging current usually flows! Fortunately, this condition often lasts only a few seconds or minutes. Then the chemistry inside ensures that the electricity returns to bearable areas. One should know this, however, because one observed from time to timeInexplicable fuse death immediately after starting the journey can be caused by a severely discharged battery.

The battery is never lower than to the minimum voltage that almost 7% greater than the total discharge border is located , to be operated. A discharge to the deep discharge limit already nibbles considerably on the battery life, a discharge below the deep discharge limit can lead to the instant (chemical) destruction of cells. It is advisable to stay well above the minimum voltage, because the condition applies to every single cell connected in series (at 6 V three, at 12 V six), which are not individually accessible and controllable. It could then possibly go something like: "The lake was a meter deep on average, but the cow drowned ..."

The polarity reversal a cell can be fatal for a battery, usually it loses noticeably in capacity or is a case for disposal. How can it come to that? In the course of a battery life, the individual cells can age differently, ie the cell capacities are then no longer the same when charged. Let us assume that 5 cells still have 5Ah, the sixth has always been neglected with regard to its fluid level and has "aged" down to 3 Ah. If this 12 V battery is now loaded, the same discharge current flows through all cells connected in series. If the healthy - let's assume - have now delivered 3 Ah, they still have 2 Ah "on top", but our problem cell is already empty, because it only had 3 Ah. If the discharge current continues to flow,if it is discharged below its deep discharge limit, its cell voltage approaches zero. Externally, this can go unnoticed so far, as her 5 sisters may still bring 5 * 2.2 V = 11.0 V to the external connections. If the discharge current continues to flow through all 6 cells as before, the cell voltage of the battered cell begins to reverse polarity. The chemical reactions change the material structure of the plates and primarily cause a strong increase in the internal resistance of the killed cell. This appears to the outside in such a way that if the battery charging voltage is correct, only a very small charging current flows, which signals an alleged full charge. When loaded, the terminal voltage of the battery collapses immediately to well below 12 V. The battery is simply dead,resuscitation is no longer possible.

All characteristics of the battery, including the voltage characteristics, are temperature-dependent. A mean value of -4 mV / K for the temperature curve of the charging voltage per cell results from various sources [3]. Gassing and deep discharge limits change in a similar way.

optimal Charging voltage in V Battery temperature	cell	6 V battery	12 V battery
40 ° C	2.24	6.72	13.44
25 ° C	2.30	6.90	13.80
10 ° C	2.36	7.08	14.16
-10 ° C	2.44	7.32	14.64

Table V.2-2: Optimal charging voltage depending on the temperature

Important conclusion:

F ÜR the predominant summer operation, the charging voltage should be two and four tenths of a volt set lower than 25 ° C (that is, 6.7 V and 13.4 V), then it is in the bathing weather period on the safe side and reaches in any case the fatal gassing limit! Of course, this is only possible if the controller has a setting option.

Fleece and gel batteries differ in their structure from the usual liquid batteries in that the sulfuric acid is absorbed in glass fleece mats (fleece) or bound in silica (gel). Unfortunately it has become common in popular usage to incorrectly refer to the fleece battery as a gel battery. Fleece and gel batteries are maintenance-free (leak-proof) and can usually be operated in any position. The gel battery has a higher internal resistance than the fleece battery, which is why it is less suitable as a starter battery. The low self-discharge rate of the maintenance-free batteries should be emphasized , which predestines them for use in "winter dormant" and little-moving oldtimers.

Example data for fleece battery VISION CP450 (6 V / 4.5 Ah)

all information on the technical data was taken from [6]

Installation position: any

Measurement condition for capacity: 1/20 of the Ah number, ie at I = 0.225 A.

Max. Charging current: 1.8 A

Max. Discharge current: 67.5 A for 5 s

Self-discharge rate at 20 ° C: approx. 3% per month

Fig. V.2-3: Optimal charging voltage Fig. V.2-4: Capacity as a function of

depending on the temperature, temperature and discharge current

Fig. V.2-5: Loss of capacity due to Fig. V.2-6: Maximum capacity

Self-discharge over 6 months loss due to aging

Nominal capacity and available capacity

At the beginning of this section it was already pointed out that the nominal capacity of a battery is only a constructively intended value. This value is usually part of the trade name or printed on the housing of the battery.

However, the currently available capacity depends on several factors such as the state of charge, temperature, battery age and the size of the load current.

In order to enable comparability when handling batteries with different nominal capacities, the load or charging current is expediently related to the nominal capacity. Replacing the unit of measurement Ah with A results in 100% current. In the above example, a 100% load on the 4.5 Ah battery corresponds to a current drain of 4.5 A. This is also symbolically written as 1C (1 corresponds to the factor 1, i.e. 100%; C of current = current). 0.05C would then be 0.225A or 2C would mean 9A.

In this respect, it is sufficient, for example, to state that the optimal charging current for lead-acid batteries should be 0.1C. The specific value can easily be calculated based on the nominal capacity. ¹ )

Diagram V.2-4, which shows the dependence of the available capacity on the load current and temperature, can therefore also be used as a good approximation for other nominal capacities.

Example calculation: A battery has a nominal capacity of 11 Ah and it is 3 years old. What capacity is available after a full charge with a constant load current of 11 A and an ambient temperature of 0 ° C?

The age of the battery reduces the available capacity according to diagram V.2-6 by 28%, ie about 11Ah - 28% = 7.9Ah.

A load current of 11A corresponds to the 1C characteristic curve in diagram V.2-4 and this results in a capacity drop to 45% at 0 ° C, ie 7.9Ah * 0.45 = 3.5 Ah.

Result: Under the specified conditions, the fully charged

11 Ah battery only 3.5 Ah available.

¹ ) In other representations, an I symbol with an index is sometimes used instead of the C symbol (e.g. 0.1C = I ₁₀ or 0.05C = I ₂₀ etc.)

V.2.2 Function test

Determination of the rest voltage

The battery to be tested is charged with the available charging technology in accordance with regulations and to the best of our knowledge and belief. The voltage at the battery terminals is occasionally measured during the charging process. 6.9 V or 13.8 V must not be exceeded at room temperature (see Table V.2-2) in order to remain below the gassing limit.

After charging and disconnecting from the charger, the battery is left to its own devices for at least 2 hours or, better still, overnight. The rest voltage is then measured. If it is 6.3 V or 12.6 V or more, that's okay. Values below this usually indicate advanced aging.

With 5.9 V or 11.9 V or less, the battery can hardly be used.

Determination of the capacity

It is actually not possible to determine the capacity of a battery without knowing and complying with the conditions specified by the manufacturer specifically for its product.

However, in order to still determine a reference value, reasonable measurement conditions are given as follows:

Carried out at room temperature 25 ° C

1. Full charge

2. Rest for a few hours or overnight

3. Determination of the discharge time at

Discharge current in A of one twentieth of the number of ampere-hours (0.05C) and

up to a final voltage of 5.6 V or 11.2 V (see Tab. V.2-2)

The capacity then results from the product of the (mean) discharge current in A and

the discharge time in hours.

Example: 12 V battery, nominal capacity 14 Ah

Discharge current 0.05C -> 0.7 A

Discharge power: 0.7 A * 12 V = 8.4 W.

Approximate realization with available incandescent lamps: 5 W + 2W + 1.2 W = 8.2 W

The lamps are connected and from that moment the time starts running.

It is advisable to measure and register the falling battery voltage every hour.

When 12.0 V is reached, the actual discharge current I (eg 0.65 A) is measured and noted.

If the terminal voltage has dropped to 11.2 V, the discharge is aborted and the time is stopped (eg 17 h).

The current capacity of the battery is therefore 0.65 A * 17 h = 11.05 Ah

The measured capacity value allows the assessment of the continuous load capacity of the battery at room temperature. If the capacity falls below 50% of the nominal capacity, a replacement should be considered. The capacity value is heavily dependent on the specific conditions such as temperature, size of the discharge current and battery age; the applicable tendencies can be read off from the diagrams V.2-4 and V.2-6.

Determination of the internal resistance

In addition to the terminal voltage value (open circuit voltage) and the capacity - especially in vehicles with an electric starter - the internal resistance is decisive for the usability of a battery . The voltage and capacity may still be OK, but when the button is pressed, the electric starter can be quite weak. The very high current of a few 10 A required for a short time during the start-up process causes a voltage drop through the aging-related increase in internal resistance of the battery, which greatly reduces the external terminal voltage. The battery can perhaps be used for other purposes, but no longer as a starter battery. With the kick starter vehiclesInitially, only energy is required to operate the ignition. The maximum power consumption with the ignition switched on is around 4 A (6 V system) or 2.5 A (12 V system). In this case, a moderately increased internal resistance is less critical, the batteries can be used significantly longer under the circumstances.

To find out something about the internal resistance-related age of the battery, we can measure the voltage difference for "ignition on" / "ignition off". Of course, this only works in vehicles with battery ignition, where the current specified above (4 A or 2.5 A) is drawn from the ignition coil.

The "on" / "off" interplay occurs every second until a stable voltage difference is established. This should not be greater than 0.3 V (6 V system) or 0.5 V (12 V system), which corresponds to 75 m Ω or 200 m Ω . It makes sense to do this test once a year (e.g. before the winter break) and to note the voltage difference. The increase in this difference as the battery ages is a good indicator of the remaining capacity. The voltage measurement must take place directly at the battery terminals!

A headlight bulb , for example, can be used to measure the internal resistance of the battery outside the vehicle . You connect the light bulb, wait about a minute until the battery voltage has dropped to a stable value U1 and then interrupt the circuit, whereby the voltage immediately jumps to a higher value U2. The load change should be repeated every second until the voltage differences U2-U1 remain stable. Finally, the lamp current I is determined.

The internal resistance R _i must then be calculated as follows and is preferably given in mΩ because of the small number of measurements:

R _i = (U2-U1) / I.

V.2.3 Check operating conditions in the vehicle electrical system

3 Measurements with great informative value are carried out directly on the battery terminals in the vehicle. The battery should be fully charged and left unloaded for at least half a day. The given orientation values apply at temperatures of 20 ... 25 ° C.

a) Measurement of the open-circuit voltage. Setpoints: 6.3 V or higher or 12.6 V or higher.

(see also section V.2.1 Function test -> open circuit voltage).

The open-circuit voltage measurement provides information about the extent to which the aging process of the battery has progressed.

b) Switch on the ignition. The battery is now (disregarding the control light), especially the ignition coil when the interrupter contact is closed (this state may have to be brought about by slowly moving the kick starter). In the 6 V system, the battery is loaded with around 4 A and in the 12 V system with 2.7 A. The battery voltage drops suddenly and then further slowly due to chemical processes. After about 30 s, the voltage should assume a stable value that is not lower than 6.0 V or 12.0 V.

If the values are significantly lower than 5.9 V or 11.8 V, it can be concluded that the battery is no longer the youngest, which may be due to the duration of its use or the treatment it has received. The consequence can be that ignition problems occur when starting the vehicle (battery ignition!).

c) Start the engine. At a speed that corresponds to about 50 km / h in city traffic, the LiMa delivers enough voltage to supply consumers (headlights on!) And the battery with power. We now measure the charging voltage at the battery terminals in normal operation, which is optimally 6.9 V (+0 -0.2) V or 13.8 V (+0 -0.4) V at a temperature of 25 ° C (see Table V.2-2).

Charging voltages above 7.0 V or 14.0 V reduce the service life of the battery, since no further charging takes place, only harmful, increased gassing occurs.

In the case of electro-mechanical controllers, deviations from the optimum range can be compensated for by fine adjustment of the charging voltage at the controller contact (see Section A.2.2 or B.3.2). Since the on-board voltage can change by a few tenths of a volt in the speed range due to the functional principle of the electro-mechanical controller, the usual operating conditions (sporty or restrained driving style) should be taken into account as far as possible when making fine adjustments.

Usually nothing can be calibrated with conventional electronic controllers. In this respect , one only learns something about the fate of the battery as determined by the charging voltage during the measurement.

V.4 Some typical error patterns

V.4.1 Battery is not sufficiently charged, engine cuts out when idling

Measurement of the battery charging voltage during operation according to Section V.2.3 c. If it does not correspond to the optimal value, the controller, cables and LiMa must be checked for correct function (see corresponding sections under A for 6 V systems and B for 12 V systems).

If the charging voltage is OK, but the battery voltage goes to its knees every time with idle and light, the battery is very likely to be exhausted because it can no longer store any charge. This can go so far that the voltage for the ignition is no longer sufficient and the engine stops when the engine is idling, especially when the traffic light turns green again. Who does not know that...

V.4.2 Charge control does not go out or is glowing

The charge control lamp is generally "suspended" between battery plus and generator plus.

Fig. V.4-1: The function of the charge control lamp

Whether the LKL lights up or remains dark depends on the voltage U _{lkl that is generated} across it. U _lkl is the differential voltage between the battery voltage U _b and the current generator voltage U _g :

U _lkl = U _b - U _g .

If the LKL is an incandescent lamp , it does not care whether the voltage U _lkl at the end is positive or negative, which makes it glow. This does not apply if, for example, an LED was used for the LKL , for which the polarity is important!

Example 1: Motor is at a standstill, generator voltage U _g is therefore zero, battery voltage U _b is 6 V.

Ulkl = 6 V - 0 V = 6 V -> LKL lights up.

Example 2: Motor is running, generator voltage U _g is 6.9 V, battery voltage U _b is 6.9 V.

Ulkl = 6.9 V - 6.9 V = 0 V -> LKL does not light up.

Once this functional principle of the LKL has been understood, the systematic search for the cause of a malfunction will not be difficult.

From the examples, the cause of the alarming permanent lighting of the LKL can already be deduced : The generator voltage at D + / 61 remains zero during operation as well as at standstill. Faults can be found in LiMa, controller and cabling. The LKL is actually there to signal this error condition!

If the LiMa at D + / 61 reaches a few volts, which is, however, lower than the battery voltage, the battery is of course also not charged and the LKL is constantly glowing weakly due to the lower voltage difference.

If the LKL glows continuously and the battery is more poorly than properly charged, an excessive voltage drop (ailing contacts, fuse, cables, ignition light switch) may be the cause. Instead of looking for the cause, the operator may have simply turned up the regulator to compensate for the voltage drops. At D + / 61 there are e.g. 7.7 V, but only 6.9 V come to the battery:

U _lkl = 6.9 V - 7.7 V = -0.8 V.

Since the incandescent lamp does not care about the polarity of the voltage, -0.8 V may be enough to make the small control lamp glow visibly.

If the LKL glows and becomes even brighter with increasing speed, there may also be a fault in the controller that is no longer able to regulate the on-board voltage sufficiently.

Conclusion : Look for the causes of the impermissible voltage difference between D + / 61 and battery plus in normal operation!

In the case of the electronic controller in the 6 V system, however, the glow is normal because the voltage at D + / 61 is always approx. 0.8 V higher than the battery voltage due to the function of the reverse current diode. However, this is not the case with electronic 12 V regulators, as they normally do not have a reverse current diode.

Interesting individual cases - loose rivet contact

Despite the correct setting of an electromechanical regulator, the charge control lamp (LKL) glowed after it was installed. When removing the controller (thankfully made available by Lastnesel /mz-forum.com for the investigation) one had the feeling that the plug contact (51) was a bit warmer than with the correctly functioning exchange regulator was. However, since nothing could be seen at first glance, the controller was measured again and the correct adjustment confirmed. By chance it was found that the riveted flat contact of the controller could be moved a little. By measuring the resistance, the poor electrical contact when the contact tab moved could quickly be detected. Due to the resulting increased contact resistance on the contact lug, the charging voltage was a few 100mV lower than the voltage on D +. This was enough to make the LKL glow. The rivets were re-pressed and the error was eliminated.

V.4.3 Ignition fails

Weak battery: possible cause when starting or idling, see explanation in section V.4.1

As an introduction to the targeted search , the voltages at terminals 1 and 15 of the ignition coil are measured:

15 to ground: When the ignition is switched on and the breaker contact is closed, almost the full on-board voltage> 6.0 V or> 12.0 V must be applied. If only 5.5 V or less or 11 V or less arrive here, a serious voltage drop must be looked for (see example in Section V.1.2)

1 to ground: Interrupter contact closed: 0.0 ... 0.1 V - if higher voltages are measured, the ignition contact or the cables leading to it must be examined.

Breaker contact open: On- board voltage is present (> 6.0 V or> 12.0 V)

If the voltage values are OK and the trivial tests (e.g. insert a candle that is really as good as new ) have failed, all that remains is to examine all the individual components belonging to the ignition system (see Section A.4 or B.5).

The operational test with a minimum ignition circuit is advisable in order to exclude sources of error that do not affect the ignition system in the narrower sense. For 6 V and 12 V systems, see Section A.4.4.

V.5 horn

The horn models used by MZ generally work with DC voltage (6 V or 12 V) and work according to the principle of the "Wagnerian hammer".

Fig. V.5-1: View into the interior of an older 6-V horn from

the trim and membrane have been removed

Fig. V.5-2: Individual parts of the membrane unit from the outside (1) to the inside (9)

When the membrane is in the rest position, the contact in Fig. V.5-3 (K) is closed and the voltage applied to the horn connections drives a current through the solenoid. The resulting magnetic field pulls the iron yoke attached to the membrane inwards, Fig. V.5-2 [8], and at the same time pushes the contact [K] attached to the Pertinax plate downwards. The circuit is interrupted, the tensile force becomes zero and the membrane springs outwards again. The contact (K) closes again and the game starts over. The vibrations occur so quickly that an audible, loud sound is produced that is emitted by the membrane like a loudspeaker.

Fig. V.5-3: Contact (K) moved by the membrane and external adjusting screw (S)

If the horn fails, there is almost always a contact or adjustment problem, which can usually be easily rectified. To do this, first remove the decorative panel (if present) and the membrane. The membrane unit consists of a large number of individual parts (see Fig. V.5-2), the assembly sequence of which you should definitely record.

The contact (K) must be closed when the membrane is removed. If it is visibly open, there is a gross adjustment error. The adjusting screw (S) on the outer underside of the horn must then be turned clockwise until the contact closes safely (!).

The resistance is now measured on the cleaned connection terminals with the multimeter. If it is well above 0.6  Ω (6 V horn) or 1.2  Ω (12 V horn), the contact (K) must be cleaned. The resistance values are empirical, they can vary depending on the model. The contact is pressed down strongly (the restoring force is relatively large!) And both contact surfaces are sanded with a strip of hard parchment paper. Only in the case of stubborn corrosion / erosion may exceptionally help with sandpaper (500 or finer). You can immediately convince yourself of the success of the action by measuring the resistance again.

If the contact is opened during the resistance measurement, the display jumps to "infinite". If this is not the case - which is extremely rare - there may be a short circuit due to insulation damage or a defective interference suppression capacitor. In the horn model shown in Fig. V.5-3, the interference suppression capacitor can be found under the small Pertinax plate with the contact (K).

If all irregularities have been eliminated up to this point, the horn - including the decorative panel with cardboard or Pertinax disc - is fully assembled. The fastening screws must be tightened so that they are fully tightened; if the screw connection is loose, neither a clean sound nor a reliable function can be achieved.

Before voltage is applied, the horn must be pre-adjusted , otherwise the setting will turn into a single "blind flight". To do this, proceed as follows: The multimeter is connected and the resistance value is observed. Depending on the situation, we proceed according to case 1 or case 2:

Case 1: Display "infinite". The membrane opened the contact when the horn was screwed together. With the adjusting screw on the base of the horn, the point is searched clockwise at which the display switches to the low resistance value. To be on the safe side and keep the resistance low, let's turn it a quarter turn.

Case 2: Display "low resistance value - approx. 0.5  Ω ". The adjusting screw is brought anti-clockwise to the point where the display jumps to "infinite". Then the adjusting screw is turned back again until the low resistance value is displayed, just to be on the safe side we turn a quarter turn further to keep the low value.

Now it is tested for the last time whether the default setting is correct (see Fig. V.5-4). In the idle state, the low resistance value - in the example 0.5  Ω - is displayed. We boldly press the membrane inwards with our thumbs - the display instantly switches to "infinite".

Fig. V.5-4 left: membrane in rest position (0.5Ω), right: membrane pressed in (resistance infinite)

It is essential to use a well-charged vehicle battery for the sound setting or the operational test .

The estimate of the peak current for the 6 V horn shown above gives

I = 6V / 0.5 Ω = 12 A. It is therefore clear that DC power supplies that are able to deliver significantly less current are absolutely unsuitable for commissioning , even if the actual mean operating current is significantly lower (at 6- V-horns 2 ... 5 A, with 12-V-horns approx. 1 ... 2 A). Equally unsuitable are chargers that could perhaps supply the current, but do not allow the setting of a clean tone because of the usually unsmoothed, pulsating direct current.

If we connect the voltage, either a continuous tone sounds or at least a powerful "pop" of the membrane. By carefully turning the adjusting screw in 1/8 steps, you are looking for the loudest and cleanest sound. In the end, it will be barely more than one turn from the pre-adjustment point.

Since the horn's output is quite generous at 15 ... 30 W, the horn should not be played for too long while it is being set, in order not to overheat the inner coil and to protect the neighbors' nerves.

For the described setting procedure it was assumed that the horn is in its original condition, i.e. that parts are neither missing nor put together in the wrong order.

Another degree of freedom when setting the horn is the distance between the iron yoke of the membrane Fig. V.5-2 (8) and the iron coil core (air gap in the rest position). Depending on the design of the horn, it can be changed with the diaphragm pin (9) and the diaphragm nut (1) or by adding spacers. If the distance is too great, the volume remains low. If the distance is reduced, it must be ensured that the iron yoke of the membrane can vibrate freely without touching the inner iron core. After changing the distance, the horn must be readjusted with the adjusting screw (S).

From the text it is surely clear that the "intonation" of the horn is not quite as trivial as it appears at first glance. The most common mistakes are haphazard "rattling" at the adjusting screw, corroded contacts (outside and inside), non-optimal air gap and unsuitable voltage sources. Often times I couldn't help but smile when, after the first inspection of the horns entrusted to me, it became clear at which point the last test pilot had broken off his blind flight in frustration ...

V.6 Electronic tachometer (eDZM)

A rotating magnet system (air-core meter) was used as the measuring mechanism for the speed display. In contrast to the classic cross-coil measuring mechanism, the coils, offset by 90 °, are arranged as a stator and the rotatable magnet as a rotor in the inner air space of the coils (see Fig.

Fig. V.6-1: Basic and real structure (pointer and scale removed)

a rotary magnet measuring mechanism

The currents I1 and I2 generate the magnetic field components H1 and H2 in the coils 1 and 2 , which are superimposed in the inner air space to form the resulting magnetic field H. The rotary magnet rotates like the needle of a compass in the resulting direction of H and remains in this position.

Remarkably,

· That this measurement principle works without return spring gets along (= robust mechanical construction)

· That if both current polarities are used, a display in all 4 quadrants, ie up to 360 °, is possible

· That the display is independent of the absolute magnitude of the currents. Only the ratio of the two currents determines the display angle.

It is obvious that the generation of the two coil currents in the correct ratio to one another from the measured variable (eg from a frequency proportional to the speed) requires relatively complex signal processing. The LM1819N circuit , which contains all the necessary components in an integrated form, was therefore used to control this measuring mechanism .

Fig. V.6-2: Tachometer board with control circuit LM1819N

(Photo: MZ Werner / mz-forum.com)

The circuit read out from the board (Fig. V.6-4) largely corresponds to the typical application published in the data sheet for the circuit LM1819N (National Semiconductors, 1995 edition). D2 serves as reverse polarity protection and D1 as overvoltage protection. With D3 a reference potential of about 5V is generated at (A), so that, based on this, negative and positive voltages are possible at (B) and (C). In front of the internal signal input at Pin10, a multi-stage low-pass circuit ensures that the signal is formed and at the same time effectively suppresses interference peaks. This RC combination can be designed differently, depending on whether the speed signal is taken from the ignition or the phases of the three-phase LiMa. The elements on pins 5, 6, 8, 9 determine the sensitivity of the deflection of the pointer as a function of the Measurand. With R5 the display can therefore be varied within certain limits.

N [min ^-1 ]	600	1200	1800	2400	3000	3600	4200	4800	5400
Signal frequency [Hz]
Ignition box (ETZ, Rotax) 1 pulse / KWU *)	10	20th	30th	40	50	60	70	80	90
LiMa phase (ETZ) 4 periods / KWU	40	80	120	160	200	240	280	320	360
LiMa phase (Rotax) 6 periods / KWU	60	120	180	240	300	360	420	480	540

*) KWU = crankshaft revolution

Table V.6-3: Display value depending on the signal frequency for various DZM deployment types

Fig. V.6-4: Circuit read out from the board (corresponds to the typical application of the LM1819N as a tachometer)

Fig. V.6-5: Measured voltages (a) on the cross-wound bobbins and calculated angle of rotation (b) depending on the signal frequency (application type: ETZ LiMa-Phase)

For a DZM (application type: ETZ LiMa-Phase) the voltages across the cross-wound coils (U _CA , U _BA ) were measured and shown in Figure V.6-5 (a). Although the curve deviates significantly from the circular shape, the back calculation of the resulting angles shows an astonishingly good display linearity (see Fig. V.6-5).

The relationship between speed display in min ^-1 and injected signal frequency in Hz can be removed from the table V.6-3.

(Reference: 3000 min ^-1 - 200 Hz).

A DC voltage source of around 3 V is required to check the function of the measuring mechanism. The test is carried out according to Fig. V.6-6. The connection diagram corresponds to the top view of the threaded pins on the rear of the measuring mechanism (as in Fig. V.6-2).

Fig. V.6-6: Functional test of the rotary magnet measuring mechanism

The functional test of the circuit board will have to be limited to checking the operating potentials on the circuit after the operating voltage has been applied to the +12 V and ground connections: Pin 7 and 14 each zero volts, pin 13 about +11.4 V, pin 1 about +5 V.

In the complete state, the function of the eDZM can be checked by applying an AC voltage of ≥20 Vpp to the signal input after connecting the operating voltage. At 50 Hz, depending on the type of use of the DZM, a display of 3600 min ^-1 , 900 min ^-1 or 600 min ^{-1 will} result.

Tests have shown that a square wave form, in contrast to a sinus wave form, ensures the correct display even for lower signal voltages.

Thanks to mzkay /mz-forum.com for providing us with

DZM devices on which metrological examinations could be carried out.

V.7 The setting of the breaker ignition

The steps for setting the ignition are shown using the example of the MZ standard alternator 6V / 60W and can be applied to the RT alternator 6V / 30W or the ETZ three-phase alternator 14V / 15A.

Preliminary remark: If the crankshaft has a perceptible radial play on the cam or if the crankshaft stub with rotor and cams “wobbles” perceptibly (> 0.1mm), precise setting of the ignition is impossible or speed-dependent malfunctions can occur. A new storage or a general overhaul of the engine is inevitable in such a case!

Fig. V.7-1: Alternator 6V / 60W with breaker ignition

(1) Plug contact for cable to ignition coil terminal (1)

A: Interrupter contact fixing screw

B: eccentric adjusting screw

K: Breaker hammer / contact spacing

C: Break plate fixing screws

Q: Lubricating felt in metal surround

Test: Connection points for test lamp

Preparation: Cams and interrupter contacts are cleaned and checked for mechanical integrity.

If necessary, the contacts can be processed with a contact file (very flat file with a special cut) so that when closed they rest over the entire surface. In the repair instructions it is recommended to remove the breaker hammer for this work. However, it is more practical to insert the file between the two contacts and to press them lightly against one another while filing so that the parallelism of the contact surfaces is automatically maintained. File chips must be carefully removed after processing!

If the craters are beyond recovery, the interrupter must be replaced. The breaker hammer is pushed onto the shaft that has been wetted with a little breaker oil (eg ADDINOL U 1500) and fixed.

Severe contact erosion in a short period of time can be caused by a defective ignition capacitor, among other things. With the help of a suitable digital multimeter, capacity (target: 0.22 µF + 20 / -10%) and insulation resistance (target:> 20 M W ) can be checked.

Setting the contact distance K: Turn the crankshaft with a 14 or 13 ring spanner (clockwise) (candle unscrewed) so that the cam opens the interrupter contact the widest at its highest point (cam peak).

The contact must not decrease or even close at any point on the Nockenberg (“Nockenberg with saddle”). This can possibly be the cause of an increased tendency to reverse the direction of rotation of the motor at low speed. In this case, the cam must be replaced by a perfect one with a constant radius "on the mountain".

Loosen screw A (see Fig. V.7-1) just enough so that the contact with the eccentric screw B can be moved without using excessive force.

In the case of breaker plates without an eccentric screw, breaker contacts with so-called notch adjustment are used. A suitable screwdriver is inserted into a notch and the contact is moved by carefully tapping the screwdriver handle with a piece of wood.

The setting dimension is usually given as 0.4 mm. The check is carried out with a corresponding feeler gauge. Distance gauges 0.3 / 0.6 or 0.4 / 0.6 are included in the original vehicle tool kit. If the distance cannot be adjusted, a worn foot of the breaker hammer may be the cause. The contact is then unusable and must be renewed.

As a final check, we turn the crankshaft 360 ° in the direction of engine rotation (clockwise) and check the distance with the feeler gauge. The contact spacing often changes again when the fastening screw A is tightened . The procedure must then be repeated until the specified breaker distance is met in the fixed state.

Tools for setting the ignition position:

· Test lamp 12V (might as well be used for 6 V systems)

· Zündeinstelllehre for determining the piston position OT ( o berer T otpunkt) and the ignition position before TDC.

In [2] 1st edition p. 205, Fig. 4.33 and 4.34, simple setting gauges for vertical or inclined plug holes are shown.

In addition, various MZ repair instructions refer to special tools such as the ignition setting gauge H8-2104-3 (see Fig. V.7-2) or H8-1408-3 (see Fig. V.7-3). However, these are sought-after collector's items and are more intended for showcases than show pieces, because they are now traded at astronomical prices.

Picture V.7-2: Zündeinstelllehre H8-2104-3 image V.7-3: Zündeinstelllehre H8-1408-3

for oblique candle hole for vertical candle hole

(Photos: Christof, mz-forum.com)

Setting tools with a dial gauge and plug thread adapter (Fig. V.7-4) for vertical plug holes are more practical and easier to obtain . For inclined candle holes only the self-made degree disc or comparable aids remain .

Figure V.7-5 shows a simple self-made solution. An old socket wrench socket (SW 13 or SW 14) is prepared so that it can be clamped with two small screws on the hexagon head of the M7 rotor screw. A correspondingly angled pointer (bicycle spoke ) is attached to this clamping piece. A paper strip is placed on the housing of the alternator, which has the markings for TDC and the preignition - in the illustration for example for 3 ± 0.5mm from TDC. The dimensions for the division can be found in the tables for the corresponding motor type in Appendix Z.7.

Fig. V.7-4: Dial gauge with plug adapter and feeler pin extension for vertical plug hole

Fig. V.7-5: Pointer clamped on the hexagonal head and applied marking strips (example for ES150, target: 3 mm from OT)

Setting the ignition position

The ignition position is often referred to colloquially as the ignition point (ZZP) , although strictly speaking it is not a time parameter.

After the candle has been unscrewed, the components of the existing ignition setting gauge are mounted.

The two screws C of the breaker plate (Fig. V.7-1) are only loosened so far that the plate moves when gentle blows are given to the nose located between the screws (tap on a screwdriver with a piece of wood).

The test lamp is between the capacitor connection (1) and ground

(see connection points Prü in Fig. V.7-1).

The ignition is switched on with the ignition light switch, the idle and charge control lamps light up. However, current also flows through the ignition coil (3 ... 4 A) when the breaker contact is closed. The adjustment process should therefore not take too long in order not to overheat the ignition coil and to save the battery.

Turning the crankshaft searches for top dead center (TDC) . It is reached when the screwed-in dial indicator shows a maximum or the feeler rod protrudes the furthest from the plug hole. The breaker contact is now open and the test lamp lights up.

TDC is the zero or reference point (= 0 mm before TDC or = 0 ° before TDC) for the ignition timing. The pre-ignition in mm before TDC or the pre-ignition angle in ° before TDC is always related to it.

(a) Rough presetting:

The crankshaft is turned counter-clockwise until the required value of the pre-ignition on the dial gauge, feeler gauge, degree disc or marking strip is reached. The exact values depend on the engine and must always be taken from the relevant operating instructions . In terms of magnitude, they are around 3 mm or 22 ° before TDC.

If the interrupter is equipped with a centrifugal adjustment (before 1970), the centrifugal weights must be pushed completely outwards during the entire adjustment using a device provided for this purpose.

By moving the interrupter plate in the "early" or "late" direction (see Fig. V.7-1), the position can be found in which the test lamp has just reached the switching point by changing "lights" <-> "not lights" signals. This switching point corresponds to the position at which the ignition spark is triggered.

The contact on the Nockenberg is open and the test lamp lights up,

it is closed in the cam valley and the test lamp remains dark.

(b) Fine adjustment, correction:

The ignition position is always checked by turning the crankshaft in the direction of engine rotation (clockwise) past the switching point while observing the setting gauge and test lamp. Once the breaker plate is fixed, the setting values must be checked again and corrected if necessary.

Finally, the contact distance must be checked again. If it has changed unintentionally when moving the breaker plate (which unfortunately is often the case), there is no other option than to repeat the entire setting procedure, whereby the corrections are getting smaller and smaller and you will find a satisfactory one after several such "cycles" State is approaching.

Various tips and hints for setting the ignition

When assembling the interrupter contact , make sure that the guide pin Z goes into the intended hole in the interrupter plate (see Fig. V.7-6).

Fig. V.7-6: Guide pin Z of the breaker contact and breaker plate

The maintenance intervals for the breaker ignition (contact distance, ignition position) were specified for the RT types with 2000 km, with the ES types with 2500 km and from TS to ETZ with 5000 km. A check at the beginning of the season is definitely recommended.

After installing a new breaker contact, the contact distance must be checked after approx. 500km, since experience shows that the contact surface (hammer base) of the breaker hammer grinds quickly on the cam at the beginning.

The lubricating felt F (Fig. V.7-1) is adjusted so that it only touches the cam at the highest elevation (cam peak). After setting or checking old grease residue from cams to remove and 2 ... 3 drops breaker oil (eg ADDINOL U 1500) on the Schmierfilz F to give.

The felt strip under the breaker hammer prevents breaker oil thrown off the cam from contaminating the contacts. It has to be there!

Since the contact distance with a fixed breaker plate becomes smaller during operation due to wear of the breaker hammer on the cam, the ZZP shifts in the “late” direction.

Contact wear increases the contact distance and shifts the ZZP in the "early" direction. However, this influence is over-compensated by the wear and tear of the breaker hammer, ie the ZZP always moves towards "late" after a long period of operation.

Tip: To protect the battery and ignition coil, the cable on the capacitor (1) can be removed and the test lamp connected between the battery positive and the capacitor contact (1). The ignition remains switched off. The signaling of the test lamp is now reversed: When the contact is closed (cam valley) it lights up, when the contact is open (cam hill) it remains dark.

Why pre-ignition?

The pre-ignition basically causes the mixture to ignite before the top dead center is reached. This should lead to an optimal course of the combustion pressure after the piston has exceeded TDC. However, since the time for the pre-ignition with a fixed ignition position becomes shorter and shorter with increasing speed, the time for the pre-ignition shrinks to the same extent. With a pre-ignition angle of 22 °, for example, the pre-ignition time at 1000 min ^{-1 is} just under 4 ms, but only 0.6 ms at 6000 min ^-1 . The example is intended to make it clear that excessive precision when setting a fixed pre-ignition position is actually not justified. With a speed-dependent pre-ignition (ignition curve)this effect can be more or less counteracted. The MZ two-stroke engines - including those with centrifugal adjustment - generally have a fixed ignition position at operating speed.

What is the meaning of the contact distance?

During opening, the voltage across the contact increases rapidly and can reach tens to hundreds of volts until the spark triggered on the candle stops the voltage increase. The rate of voltage rise is determined by the capacitance of the ignition capacitor; the smaller the capacitance, the greater the rate of rise.

If the contact distance is too small, voltage flashovers can occur between the contacts, which leads to increased wear. The voltage flashover limit in air is around 3000 V / mm, ie when the contact is fully open (0.4 mm) there is no flashover as long as the voltage remains below 1200 V. However, if the contact is only opened 1/30 mm during the movement, the rollover limit at this point in time is only around 100V.

Problem: ZZP cannot be adjusted in the adjustment range of the base plate

The assignment of piston position and cam position is subject to tolerances. Responsible for this is the actual position of the fitting grooves on the crankshaft stub, the LiMa rotor and the cam. The problem described above can arise particularly when a new cam from re-production or unknown stocks is installed.

If an assembly error within the LiMa is definitely ruled out, the rotor can be fitted slightly rotated. To do this, the key on the crankshaft stub must be removed beforehand. An offset in clockwise direction causes the ZZP to be shifted to "early" and vice versa.

V.8 Vehicle light bulbs

The test voltage of an incandescent lamp is understood to be the operating voltage for which it is designed, ie to which electrical (e.g. power), photometric (e.g. brightness) and service life specifications refer. The values were specified in regulation ECE R 37.

nominal voltage	Test voltage according to ECE R37
6 V	6.3V
12 V	13.2 V (13.5 V for auxiliary light lamps)
24 V	28 V

There is a relationship between the actual operating voltage in the vehicle and the statistically expected service life or brightness, which is shown in Figure V.8-1. As a rule of thumb, a 5% permanent increase in voltage halves the service life and 10% consequently quarter it.

Fig. V.8-1: Relationship between service life, brightness and operating voltage

of vehicle light bulbs (source: https://de.wikipedia.org/wiki/Gl üh lampe ,

Primary source not specified)

Since the usual on-board voltages are 6.8 ... 7.0 V or 13.8 ... 14.0 V, the incandescent lamps are already operated with around 10% or 5% overvoltage. According to the diagram above, only a quarter or half of the statistical lifetimes specified by the manufacturer can be expected from the outset , since these refer to the test voltages of 6.3 V or 13.2 V.

The filament temperature reaches values of over 2000 K during operation. As a result, the differences between the cold and hot resistance of the filament are very large, they differ by a factor of about 10 (see Fig. V.8-2).

Fig. V.8-2: Current consumption (I), filament resistance (R) and power (P),

measured on a copy of a 6V / 45W headlight lamp.

The inrush current of a high beam filament measured on an oscillograph is shown in Fig. V.8-3. In order to achieve the required current yield of the voltage source, a plurality of 6-V nonwoven batteries are connected in parallel to the power was indirectly as a voltage drop across a measuring resistor of 1.5 m Ω determined.

In order to achieve the inrush current peak of over 50 A, the internal structure of the incandescent lamp must be completely cold before switching on, repeated switching on in quick succession heats the interior of the incandescent lamp quickly and reduces the inrush current peak to half or less. Likewise, there are significantly lower current peaks in the heated thread system if only a switch is made between high and low beam.

The inrush current lasts about one to two tenths of a second. During this time, the on-board voltage can "buckle", which can be expressed in a brief misfire.

Fig. V.8-3: Time curve of the inrush current of a 6V / 45W headlight

Lightbulb

Z Appendix

Z.1 Circuit of the electronic 6 V regulator MZ ELEKTRONIKUS

Fig. Z.1-1: Housing and circuit board of the ELEKTRONIKUS controller

Statement without guarantee: The metal base plate can be screwed to ground, as the circuit, diode block and power transistor are arranged in an isolated manner.

Fig. Z.1-2: Circuit of the ELEKTRONIKUS controller

The circuit of the ELEKTRONIKUS corresponds to the classic solution of a discrete analog regulator for direct current LiMas.

The BZX55C-Z-diode together with a base-emitter forward voltage (right BC212B) and the voltage drop over 1k // 15k * form the voltage reference in the regulator. If the generator voltage at D + / 61 increases, the right BC212B begins to draw current and at the same time blocks the left BC212B. As a result, the base potential at the BD243C drops and the field current at DF is reduced, so that the voltage increase at D + / 61 is counteracted.

The 15k * resistor is used as a balancing element with which the regulator voltage can be varied within small limits. For more coarse voltage adjustments, the Zener diode must be changed.

The testing of the controller outside the vehicle can be carried out according to the procedure described in Section A.3.2. The controller can easily be repaired if necessary, since the components are freely accessible.

Photos and circuit reconstruction of the ELEKTRONIKUS: TeEs (mz-forum.com)

Z.2 Electronic controller for permanently excited Rotax-LiMa

Fig. Z.2-1: Identical funnel / regulator for Rotax-LiMa

The encapsulated rectifier / regulator for the permanently excited three-phase LiMa of the Rotax motor is located in an aluminum housing with cooling fins .

Thanks to the crystal-clear potting compound, the conductor tracks on the embedded circuit board are easy to see. The controller works according to the short circuit principle. If the output voltage at terminal (30) becomes too high, the two transistors begin to carry current, so that finally 270 Ω, 100 Ω via the voltage divider one or more of the thyristors S4020 switch the respective phase for one or more half-waves in a row to ground. Part of the unused power is converted into the current-carrying diodes or thyristors, while the greater part is converted into the generator windings of the LiMa. The not inconsiderable power loss is the reason why this type of LiMa / controller can only be used for relatively small outputs (nominal output here: 190 W) in the moped and motorcycle sector. The field-regulated three-phase LiMa continues to hold its own for high electrical power in vehicles.

Fig. Z.2-2: Circuit of the rectifier / regulator block for the Rotax-LiMa

Z.3 P ermanent-excited LiMa with rectifier / regulator and ignition

Z.3.1 Regulator / rectifier for 2-phase LiMa

Low-maintenance and high-performance permanently excited alternators are also enjoying increasing popularity in older motorcycles, as the traditional 6 V direct current or 12 V three-phase LiMas are being replaced.

The special regulator circuit shown below (Fig. Z.3-1) is used to rectify and stabilize a 2-phase alternating voltage. The rectification takes place with the help of a (controllable) bridge circuit, which consists of the diodes or thyristors shown in bold.

Fig. Z.3-1: Circuit of the electronic 12 V regulator for 2-phase permanently excited LiMa

In contrast to the method widely used in the motorcycle sector of brutally short-circuiting AC or three-phase windings using thyristor switches in the event of excess voltage, the rectifier bridge remains ineffective on one side in this circuit in the same situation, since the thyristors block. However, if they act as diodes when ignited, the generator winding works via the rectifier bridge on the DC voltage output, ie on the battery and / or consumer in the on-board network.

In contrast to the three-phase LiMa with 3-phase rectifier bridge (see Section B), the resulting DC voltage after two-way rectification systematically has a relatively large pulsating component. A connected lead-acid battery or an optional capacitor should ensure sufficient smoothing of the on-board voltage outside the controller so that sensitive consumers are not impaired in their function.

The internal voltage standard (reference) is formed in a conventional manner by the lower 6.8V Zener diode Z5W in cooperation with the base-emitter path of the npn transistor 1B. A temperature-stable reference can therefore be assumed. Elements that indicate an adjustment of the battery charging voltage at different temperatures (see Fig. V.2-3) are obviously not present.

The following oscillograms (Fig. Z.3-2), which were recorded on a complete system LiMa / controller / ignition in a TS250 / 1, show the voltage curves at the controller output with different loads.

Fig. Z.3-2: Voltage curves at the controller output with different load cases

(a) When the motor is at a standstill, the battery (fleece, 12 V / 11 Ah) can be read off at an open circuit voltage of around 12.8 V.

(b) Without load (2000 min ^-1 ), the on-board voltage climbs to 14.4 V, with pulses of up to 0.5 V peak being applied to this in a random sequence. It can be clearly seen that due to insufficient power consumption, only every 2nd or 3rd rectified half-wave is switched through to the vehicle electrical system.

(c) With a load of 4x21 W and a speed of 3000 min ^-1 , the voltage drops to 13.0 V with a pulse component of 0.6 V peak. On average, this corresponds to about 13.4 V. Every half-wave is continuously switched through into the on-board network, there is nothing more to regulate.

(d) With a further increase in load to 8x21 W, the on-board voltage consequently drops further, as expected - despite the increased speed (approx. 5000 min ^-1 ) - to 11.4 V with a pulse component of 0.6 V peak.

The part to the right of the dashed line in the circuit is used to control the charge control. As long as the generated voltage is below the battery voltage, the pnp transistor 2D sends a current - multiplied by the npn transistor 1D - to the power transistor TIP47, ie the LKL lights up. The voltage feedback to transistor 1B ensures that the current at the LKL output remains limited to a few 100mA.

If a battery is used together with this type of controller, a small amount of current always flows into the controller, even when the engine is not running. The causes are distances through internal resistances and residual currents from pn junctions. Practically 0.8mA was measured on one example at 12V. That sucks a lot of 1 Ah from the battery in a 2-month winter break. This discharge is by no means critical, but you should be aware of the fact, especially when batteries with small numbers of ampere hours are used for backup.

Testing the controller

The possibilities of testing the controller outside the vehicle are very limited. If anything, they should only be done by experienced people who are aware of what exactly they are doing at each test step.

The function of the two rectifier diodes CQ735 can be checked between an AC voltage input and the + battery output (analogous to the measuring circuit in Figure B.2-2 in reverse and forward direction).

The mentioned quiescent current consumption can be measured if a 12 V battery is connected between + battery and ground. Although this is normal operation when using batteries, a 12V / 21W light bulb should be looped in beforehand to limit the current. A reading around 1 mA or below will be okay.

The function of the charge control can be checked externally. Both AC voltage inputs are connected to one another (corresponds to the situation when the motor is at a standstill). A control lamp connected to LKL against + 12V must light up. If the connection of the AC voltage inputs is disconnected and any of the two are connected to the + battery input, the LKL will go out.

An external check of the stabilization function of the controller is possible, but does not make much sense because a controllable AC voltage source with a LiMa-comparable output is required. It is easier to connect the controller to the safely functioning alternating voltage generator (prior check with aOperate the headlight lamp as a substitute load in the vehicle as in Figure B.1-3) and measure the terminal voltage on the battery or consumer. With this measurement, however, incorrect displays can easily occur, since it is a direct voltage with a more or less pulsating component and this signal form is often not displayed as a correct mean value, especially by simple digital multimeters. The safest way - as anachronistic as it may sound - is to use a conventional moving-coil pointer instrument for this special measurement. To improve its display accuracy, it should be calibrated beforehand on a 12V battery in comparison with a digital multimeter display.

Z.3.2 Electronic ignition (CDI, similar to vape)

With conventional break contact ignition, the very high ignition voltage arises from the sudden interruption of the primary ignition coil current through the break contact.

With the so-called CDI ( C ondensor D ischarge I gnition = capacitor discharge ignition), on the other hand, a capacitor charged to several 100 V is suddenly connected to the primary side of the ignition transformer using an electronic switch (see Fig. Z.3-3). This transforms the voltage jump to a few kV, so that finally a spark jumps over the candle. The CDI has a very good efficiency, since an unnecessarily long flowing primary direct current (a few A for each 180 ° KW rotation) is not necessary as with the breaker contact ignition. The voltage of the generator winding of the LiMa in the is sufficient to generate the capacitor charge voltageAs a rule, this is not the case, so a separate charging coil (L) is provided for it. This also has the advantage that the ignition can work independently of the generator and battery.

Fig. Z.3-3: Circuit of the electronic CDI (charging coil (L) and sensor coils (S) are located on the stator of the LiMa)

In the oscillogram shown below (Fig. Z.3-4) the turquoise curve shows the charging coil voltage. At around 1500 min ^-1 it already reaches peak values of over 500V. The north and south poles on the inside of the rotor, each offset by 30 °, produce 6 complete periods of the charging voltage per KW rotation (this also applies to the generator winding of the LiMa).

The two sensor coils are offset from one another by 30 ° so that there is a magnetic south pole above one when the other is being swept by a north pole or vice versa. This leads to opposing voltages which (practically almost) cancel each other out in the series connection of the two coils. In the inner circle of the rotor, however, a 30 ° segment is not equipped with a permanent magnet. If the sensor coils cover this “gap”, the compensation in the first coil and then in the second is missing. The result is that there is a positive impulse, followed by further ones, until the “rotor anomaly” has moved on. The first, large positive impulse triggers the thyristor MCR708AG, which - suddenly turned on - causesthat the charge of the 2 uF capacitor is "poured" into the primary side of the ignition transformer (points in time marked red in the oscillogram).

The following positive charging coil wave safely switches the thyristor off again via transistor 6BW so that the game can start again.

Fig. Z.3-4: Voltage-time curve at the sensor (orange) and charging coil connection (turquoise). Deflection orange: 5V / part, turquoise: 200V / part and time: 10ms / part. Red :: marking of the ignition timing

Special testing of the CDI module outside of the vehicle is not recommended because of the complex test environment required.

Special thanks go to all Foristi who contributed to the creation of the descriptions in section Z.3. have contributed in a practical and / or theoretical way!

Z.3.3 Rotax: Electronic ignition (CDI, Nippondenso)

Fig. Z.3-5: Internal circuit and connection of the Nippondenso ignition box (amplifier box).

Circuit reconstruction: dösbaddel (mz-forum.com)

Measuring points (MP):

(1): outdoor sensor, (2): indoor sensor, (3): charging voltage, (4): CDI pulse

Fig. Z.3-6: Charge voltage curve (MP 3) and CDI pulse (MP 4)

A charging voltage is generated in the stator coils L3, L4, the positive half-waves of which charge the capacitor C3 to approximately +170 V via D4, D3 (see Fig. Z.3-6).

In order to generate a sufficiently high charging voltage even at low speeds, L3 is selected to be correspondingly large. However, with increasing speed or frequency, their alternating current resistance increases steadily, which prevents C3 from charging quickly. L4 therefore takes over charge at higher speeds.

If the thyristor T1 is switched on, C3 discharges in a fraction of a millisecond and generates a narrow CDI pulse of around -170 V on the primary winding of the ignition coil, which transforms the ignition voltage pulse accordingly on the secondary side.

The switching point of the thyristor is controlled by two transmitter coils. The external encoder coil is arranged 3 ° before TDC. It generates a steep positive edge per KW revolution, which switches on the thyristor at around 1.8 V (see Fig. Z.3-7). With increasing speed, however, the flatly rising voltage of the internal encoder increases so that it reaches the switching threshold of the thyristor earlier, which pushes the ignition point forward.

Fig. Z.3-7: Encoder voltages (MP1, MP2) at lower and higher speeds.

If the CDI ignition pulse is selected as the time reference, you can see in Fig. Z.3-8 how the external encoder pulse moves away from the ignition pulse with increasing speed.

At 3530min-1 the CDI ignition pulse comes roughly before the external sensor , ie a total of 24 ° before TDC.

R3 * in the amplifier box could be provided as an adjustment element to influence the takeover point of the external and internal encoder

Fig. Z.3-8: Speed- dependent shift of the CDI ignition pulse compared to the

Control pulse from the external encoder

When the “stop” switch is pressed, the charging voltage input (MP 3) is connected to ground via diode D5. The capacitor can no longer be charged and the ignition spark disappears immediately.

Z.4 12V regulator circuit L 9480 in the ETZ

Z.4.1 Properties of the L9480 control circuit

At the beginning of the 1990s, the L 9480 regulator circuit from SGS-THOMSON Microelectronics was used in the last 2-stroke MZs with the 14V / 15A three-phase alternator.

The L 9480 works digitally as a switching regulator. Its functionality can be compared to that of an electromechanical controller, although the work of the mechanical controller contact is of course taken over by an electronic switch.

Lt. Data sheet the controller is very robust, it has a thermal overload protection, withstands battery polarity reversal, short circuit and overvoltage (up to 80V).

The nominal control voltage specified is 14.4V ± 1% at 25 ° C. Elsewhere in the data sheet, however, there is a spread of 14.1V to 14.7V, which corresponds to about ± 2%.

The control voltage has a temperature coefficient of -10mV / K. This accommodates the temperature behavior of 12V lead-acid batteries, although -24mV / K would also be required for full compensation .

The application of the circuit in the TO220 housing with three connections shown in Figure Z.4-1 is very simple.

Fig. Z.4-1: Application of the L 9480 control circuit

The wiring according to Fig. Z.4-1 shows that this - in contrast to the original electromechanical controller in the 12V-MZ - is a minus-regulating application . Connection (1) is connected to terminal (61) (= LiMa voltage after the auxiliary rectifier), connection (2) goes to the field winding connection DF-. The metal lug of the housing and connection (3) are ground, ie the circuit can be screwed onto the vehicle frame without electrical insulation.

Although the controller has internal filters, a capacitor of 0.1 ... 1µF from (1) to (3) is recommended on the input side in order to limit interference peaks. This capacitor would then also be the only additional element for the application.
Z.4.2 Measurements on the L9480 circuit

The voltage U _FW across the field winding (Fig. Z.4-1) is decisive for the excitation current through the field winding , more precisely, its mean value, since it is a pulse-shaped voltage-time curve. In the following, the addition “avg” stands for the formation of the time average: avgU _FW = U ₆₁ - avgU _OUT .

Fig. Z.4-2: Switching voltage at (2) OUT of the L 9480 controller

Since U ₆₁ fluctuates only slightly around 14V in regulated operation, it can be assumed that as the mean value of the voltage at the circuit output avgU _{OUT increases} , the above difference decreases, i.e. avgU _FW decreases, which means that the excitation current of the LiMa is reduced. The oscillograms recorded on a specimen L9480 in Fig. Z.4-2 illustrate this. For the sake of simplicity, a 12V / 4W light bulb was used as a replacement for the field winding.

If the input voltage U ₆₁ <13.6V is low, DF- is pulled against ground (there is a residual voltage of about 1.75V), ie the maximum possible excitation current flows.

If U ₆₁ rises above 13.6V, the controller output begins to switch. Since the narrow pulses are still relatively far apart, the mean value is only slightly above zero. However, the larger U ₆₁ becomes, the closer the pulses come together and at 14.06V the pulse and pulse pause are the same size, ie the time average is half of U ₆₁ , i.e. about 7V.

Fig. Z.4-3: The switching pulses for different duty cycles

If U ₆₁ continues to rise, the now negative needles move away from each other and the mean value continues to rise until it finally reaches the maximum value, namely U61. Then there are zero V across the field winding, ie the excitation is also zero.

The oscillograms in Fig. Z.4-3 show the switching pulses at different input voltages, but with a more finely resolved resolution.

The positive needles have a constant width of about 0.6 ... 0.65 ms, while the negative needles are leveled to about 0.35 ms even with larger duty cycles. The highest switching frequency was achieved with a duty cycle k = 50% with 715Hz

Figure Z.4-4 shows the mean value of the voltage across the field winding over time (green curve). This mean value over time determines the excitation current through the field winding. As expected, the curve drops with increasing generator voltage (61). In order to regulate the field current from the maximum value to zero, a generator voltage change at (61) of more than 1V is required. This low control steepness is the cause of a noticeable flexibility in the on-board voltage when the electrical load changes.

Fig. Z.4-4: Measured mean voltage avgU _FW across the field winding (green)

and period T of the pulse train as a function of the

Input voltage U ₆₁

Z.4.3 Installation in the vehicle electrical system and behavior

The L9480 regulator circuit was added to the on-board network of an ETZ150. The conversion is shown in Fig. Z.4-5.

Fig. Z.4-5: Conversion from electromechanical plus regulator to minus regulating circuit L9480 at ETZ. (a) Original circuit , (b) integr.electron. Switching regulator

The measured voltage values (see Table Z.4-6) with the built-in regulator circuit directly at the terminals of the rectifier plate (61) and (D +) are relatively high. You confirm the values from the data sheet. At 10 ° C, 14.0V would be the optimal charging voltage for a lead-acid battery, so the value is at least 0.4V higher during normal driving.

Ambient temp. 10 ° C	2000min-1	4000min-1
without light	(61) 14.67V (D +) 14.52V	(61) 14.80V (D +) 14.63V
with light	(61) 14.53V (D +) 14.32V	(61) 14.64V (D +) 14.38V

Table Z.4-6: Voltage values depending on load and speed for L9480

The two oscillograms shown in Fig. Z.4-7 and recorded in the vehicle electrical system for the same engine speed, but with different load conditions, once again illustrate the function of the integrated switching regulator L9480: The switching frequency remains approximately the same at 400Hz. Without light, however, the positive impulses are broad, with light they are narrower. The mean value over time is therefore lower under load, ie the mean voltage across the field coil and thus also the current through the field coil are greater. This corresponds to the expected behavior, since the generator needs a higher excitation at a constant speed but a higher load .

The upper oscillogram in Fig. Z.4-8 (alternating component) shows which effects the switching pulses have on the voltage in the vehicle electrical system. The steep switching edges are obviously transferred from the primary circuit (rotor) to the secondary circuit (stator), just like with a transformer. Both positive and negative needles with a pulse height of up to at least 2V can be seen. This certainly does not have a negative effect on vehicle lighting, it could become critical for electronic components (electronic ignition, navigation system, etc.), and considerable emissions are to be expected.

Fig. Z.4-7: Switching pulses at DF- with different load conditions

For comparison, the on-board voltage (alternating component) is shown in the lower oscillogram in Fig. Z.4-8 when using a standard electronic analog controller. The course is much smoother, the fluctuations of +/- 0.5V are not control oscillations, they are speed-dependent with regard to the time course and are apparently caused by magnetic field inhomogeneities of the LiMa or by differences in the individual three-phase windings.

Fig. Z.4-8: AC component of the 12 V on-board voltage for L9480 (above) and electronic ones

Analog controller (below)

Summary

The L9480 circuit is an inexpensive alternative to the standard electronic analog regulators for 12V in terms of both size and cost. This is offset by its decreasing availability, as the IC is no longer in the production program.

The high nominal voltage and the contamination of the on-board network with powerful jamming needles should be noted as disadvantageous. The voltage should be reduced by approx. 0.5V ... 0.8V by an additional diode in the line from D + to 51, especially when using dense batteries (gel, fleece), with a diode power loss of 5 ... 8W is to count.

Z.5 battery chargers and their properties

The following text is about making the connection between the charging regime (current, voltage, time) and the properties of the charger and accumulator understandable.

When does a battery have to be charged at all?

If the vehicle electrics and battery are intact, recharging is only necessary in exceptional cases, namely

• if the battery has noticeably lost its charge due to self-discharge over a long period of time. In the case of liquid lead-acid batteries, at 20 ° C, approx. 8% self-discharge per month is expected, in the case of fleece or gel batteries, 3%.
• if energy was withdrawn without sufficient recharging.

If the two situations mentioned cannot explain the loss of charge, the battery is very likely to be worn out.

Characteristics of the battery

The electrical properties of a battery are (idealized) described by 2 parameters (see Fig. Z.5-1):

1. the open circuit voltage U _B , which can be measured as voltage U at the external terminals of the battery if only the voltage measuring device is connected and no other consumers. The leeward tension is sometimes also referred to as "internal tension".
2. the internal resistance R _B , which is responsible for a drop in the terminal voltage U when a load is connected.

Figure Z.5-1: Electrical model of a rechargeable battery or a battery (term: technical voltage source)

If the battery and measuring device are at hand, both parameters can be determined by exercise. The measurement specification for U _B has already been given in point 1 (see above).

The internal resistance R _B can only be measured indirectly. To do this, a consumer must be connected to the battery (incandescent lamp), which draws about 1/5 of the ampere-hours (equivalent to 0.2C).

Example: Battery 6 V / 4.5 Ah -> 4.5 [Ah] / 5 = 0.9 [A].

Required power of the incandescent lamp: 0.9 A * 6 V = 5.4 W.

Selection of a suitable incandescent lamp with approximate data: 6 V / 5 W

The light bulb is connected and the battery voltage is observed. Initially, it may decrease slowly. If it reaches a stable value, we measure the lamp current (I _L ). and the tension. Then we disconnect the lamp. The battery voltage jumps up by a small amount. We record this difference (ΔU).

The internal resistance is now calculated

The open circuit voltage is 5.6 ... 6.5 V (or 11.2 ... 13.0 V) depending on the state of charge and the degree of aging. The internal resistance R _B is very low and is a few tens of mΩ in motorcycle batteries. For the 6 V / 4.5 Ah fleece battery CP645, for example, 22 mΩ is specified in the data sheet.

Characteristics of the charger

The constant voltage charger , like the battery, can be described as a technical voltage source with open circuit voltage U _L and internal resistance R _L (see Fig. Z.5-2). The parameters are measured in the same way as with the battery. An incandescent lamp can again be used as a test load, which causes an easily measurable voltage drop at the terminals of the charger.

This simple electrical model does not apply to chargers that change their parameters during the charging process by "observing" the temporal progression of the electrical variables at their terminals or to devices that do not supply a smooth ("pure") DC voltage, but one with pulsating components.

Fig. Z.5-2: Electrical model of a conventional DC voltage charger

For the charging process, the charger is connected to the battery, namely plus with plus and minus with minus.

Fig. Z.5-3: Battery charging with a DC voltage charger

This creates the simplest electrical circuit that electrical engineering has to offer. Our 4 parameters and current I and voltage U on the charging cable are linked by the following equations:

If all parameters of the charger and battery are known, current and voltage can be easily calculated using the above equation . The results are:

and

The formula shows the well-known fact that U _L > U _B must always be in order for a positive charging current I to flow in the specified direction. Or in the example: A 12 V battery cannot be charged with a 6 V charger.

Example calculation for charging current

The 6-V charger have an open circuit voltage of 7.0 V , the battery was pretty down, he has only 5.9 V . Its internal resistance is 0.05  Ω and the internal resistance of the charger was determined to be 0.2  Ω .

.

If the battery is connected, flow according to the formula

It is now completely irrelevant whether the charger can deliver 15A or 60A maximum before its fuse arrives or whatever values are printed on the front panel. The charging current is simply determined by the voltage difference in the numerator and the sum of the resistances in the circle in the denominator of the formula.

If the internal voltage of the battery has reached 6.9 V after a certain charging time , only:

We note that the charging current decreases to the same extent due to the internal battery voltage, which increases slowly with the state of charge. If the internal battery voltage could even reach 7 V, the charging current would be practically zero and the charging would come to a standstill. However, it would take a very, very long time to do this because the changes take place more and more slowly the closer we get to this goal.

Constant charging with optimal voltage

If the open-circuit voltage of the charger matches the charge voltage of the battery (which is optimal for the respective temperature), overcharging can obviously never occur because the charging process - as shown in the example above - ends up practically "drying up" by itself.

Figure Z.5-4 Time curve for voltage and current-limited charging for the example under consideration

This gentle and harmless charging operation can be carried out very well with an adjustable DC power supply (e.g. Peaktech 6080 or similar devices). To do this, first set the optimum final charge voltage of the battery on the supply device (see Fig. V.2-3).

Then - if the device has the current limiting function - the maximum permissible charging current by short-circuiting the voltage output sockets of the device with a cable for the duration of the setting. If nothing is specified, a tenth of the ampere-hour number applies as a guideline (equivalent to 0.1C), i.e. 0.5 A for a 5 Ah battery.

The supply device is "programmed" in this way and connected to the battery. The supply device with current limiting function automatically lowers the charging voltage at the beginning so that the set current limit is not exceeded. If the charging voltage finally climbs to the target value, the charging current begins to decrease (see Fig. Z.5-4). The charging process can be ended when the charging current has dropped to about 1/50 (equivalent to 0.02C) of the number of ampere-hours of the battery.

Continuing the charging process indefinitely would not lead to overcharging.

Constant charging with overvoltage (fast charging)

In order to shorten the charging time, the internal voltage U _{L of} simple chargers is chosen to be higher than the optimal final charging voltage of the battery. A larger charging current flows from the start, charging takes place more quickly, but after a while the charging voltage exceeds the optimal value and the charging current no longer goes back to zero. If the charging process is not interrupted either automatically or manually when the end of charging is reached, the battery will be seriously and permanently damaged because the gassing limit is exceeded.

Fig. Z.5-5 Time course for fast charging

In this charging mode, it is essential to monitor the battery voltage and to stop the charging process when the optimum end-of-charge voltage is reached. The "motorcycle" / "car" operating modes that can sometimes be selected on simple chargers are an indication that these are fast chargers whose open circuit voltage for car batteries has been increased again in order to achieve an even higher initial current for batteries with a large capacity. If these devices do not have an automatic switch-off, the charging process must be monitored with a voltmeter and terminated manually in good time.

Trickle charge

As the name suggests, the aim is to counteract the self-discharge of batteries over longer periods of time. Assuming a maximum of 10% self-discharge per month, this corresponds to a continuous discharge current of 0.1C / (24h * 30d) = 0.00014C or, in other words, 0.14 mA per 1 Ah battery capacity. With typical motorcycle battery capacities of 5 ... 15 Ah, these are equivalent discharge currents of 0.7 mA ... 2.1 mA.

A higher value can be selected to reliably compensate for self-discharge even with poor charging efficiency. Normally, the safe continuous charging current is I <0.01C, i.e. a maximum of 50 mA for the 5Ah battery and 150 mA for the 15Ah battery.

A trickle charger with U _L = 50 V and R _L = 3.6 kΩ would do this well. We check the trickle charge currents

for a 6V battery

and a 12V battery

This trickle charger is therefore suitable for both battery voltages, regardless of the battery voltage, it feeds a harmless charging current of around 10 ... 12 mA into the battery and thus reliably compensates for self-discharge. This means that trickle chargers can remain connected to the battery indefinitely.

Chargers with pulsating DC voltage

These are very simple devices, but not entirely unproblematic with regard to the charging regime. Usually they only contain the mains transformer and one or more rectifier diodes for one or two-way rectification of the down-transformed mains AC voltage. A historical representative is, for example, the "Ladefix" (TYPE GL-3-E12-6 / 6.3Bu), which can still be found often, and can be switched for 6V and 12V batteries.

Voltage and current curves are shown qualitatively in Figure Z.5-6. A peak voltage of = 10.4 V was measured on the device in the 6V regime. When connecting the battery to be charged, a current flow only occurs if the voltage of the device exceeds the battery voltage. The original peak voltage is reduced by the current load compared to the no-load case (Fig. Z.5-6 (b)). Overcharging is possible in principle, since there is still a current flow when the battery has reached its end-of-charge voltage.

Fig. Z.5-6 (a) Voltage curve without connected battery, (b) Voltage and current curve with connected battery

The end of charging must therefore be checked by measuring the battery voltage. However, since simple multimeters often give false readings for DC voltage with a pulsating component, it is better to briefly disconnect the battery from the charger for the measurement. When the optimum end-of-charge voltage is reached, the charging process is ended, otherwise it is continued. It is not recommended to leave such a charger connected to the battery for a long time, because it is not certain that the average charging current will decrease to a harmless value after charging has ended. The fixed charging times given in the operating instructions must be taken with extreme caution, as the current charge status of the battery is completely disregarded.

Chargers with 2-point control

A representative of this type is, for example, the UNILADER VOLTCRAFT TYPE 18410, which among other things allows 6- and 12V charging. The charging current can be set continuously between 20 mA and 1.4 A. Usually 0.1C, i.e. a tenth of the ampere-hour number, is set, ie the device is designed for batteries with capacities between 0.2 Ah and 14 Ah. Batteries with a capacity> 14 Ah can of course also be charged, but a longer charging time is to be expected. In Fig. Z.5-7 the function is shown based on the time curves. With the preset current, the battery is quickly charged up to the end-of-charge voltage U _o , after which the charging current is switched off electronically. Only when the terminal voltage on the battery automatically down to a lower voltage limit U _u has dropped, the charging current is back

Fig. Z.5-7 (a) Voltage curve without connected battery, (b) Voltage and current curve with connected battery

switched on . The following measurements were made on the device examined:

U _o  = 6.98 V, U _u  = 6.35 V or U _o  = 13.94 V, U _u  = 12.93 V

Since the upper switching points are safely below the gassing limit at room temperature, this device can remain on the battery for as long as required without fear of any harmful effects.

Z.6 Electronic flasher unit 12V (FER GmbH)

The flasher unit (Fig. Z.6-1) from Fahrzeugelektrik Ruhla GmbH (FER) used by MZ in the nineties is based on the Temic / Telefunken U243B circuit that was specially produced for turn signals.

Fig. Z.6-1 Board of the FER flasher unit

The circuit (Fig. Z.6-2) is specified as a standard application in the data sheet for the U243B circuit and is used slightly modified.

Fig. Z.6-2 Circuit of the FER flasher unit 2 / 4x10W

The combination C0, R0 determines the flashing frequency. An increase in resistance R0 by x percent leads to a reduction in the flashing frequency by approximately the same percentage value and vice versa.

The lamp failure is detected with the help of the voltage value across the resistor R3. If one of the two indicator lamps (front or rear) fails, the lamp current - and with it the voltage drop across R3 - inevitably drops to 50% of the nominal value. R3 is now dimensioned in such a way that the clock generator generates twice the flashing frequency at a value of less than 75% of the nominal lamp current. Since the turn signal control lamp then also flashes at twice the frequency, the driver receives information about the error status. This signaling function is only guaranteed if incandescent lamps with the prescribed power of 2x10W per side are used. Resistor R3 would have to be dimensioned differently for changed lamp power. The signaling threshold is specified internally in the circuit with 80mV.

The flasher does not work if the connection is reversed (31 <-> 49), but remains intact. Likewise, a short circuit from 49a to 31 (ground) does not lead to the destruction of the sender, so that - as is usual with thermo-electric flasher units

Extra protection of the flashing circle is not necessary.

The circuit board with components assembled in a standing position will hardly be too resistant to strong vehicle vibrations (e.g. MZ500R or similar). A subsequent fixation of the resistors and the electrolytic capacitor with non-conductive two-component adhesive is therefore recommended.

Z.7 Ignition position: conversion from (° before TDC) to (mm before TDC)

If the piston stroke H and connecting rod length L are known, the values of the angle can be calculated in

Convert ° before TDC and the ignition position in mm before TDC .

In the formulas below mean

H : piston stroke in mm (crankshaft radius R = H / 2)

L : connecting rod length in mm (= center point distance lower - upper connecting rod eye)

a : ignition angle in °

X : ignition position before TDC in mm

Convert ignition position X [mm] to ignition angle a [°]:

(X is to be used as a positive value!)

Convert ignition angle a [°] to ignition position X [mm]:

For the MZ types, the relationship between pre-ignition position and ignition angle is shown in the following tables. The third column with the name

"Distance on LiMa housing (D = 105mm) from OT" indicates the division dimensions for the paper strip according to Fig. V.7-5, based on an alternator outer diameter of D = 105mm ..

Stroke 58mm connecting rod length 125 mm IFA RT 125, RT 125/1, MZ 125/2, MZ 125/3 MM 125/1 (ES 125), MM 150 (ES 150) MM 125/2 (ES 125/1, TS 125, ETS 125) MM 150/2 (ES 150/1, TS 150, ETS 150) MM 125/3 (TS 125), MM 150/3 (TS 150) EM 125 (ETZ 125), EM 150.1, EM 150.2 (ETZ 150)
ZZP in mm v.OT	ZZP in ° v.OT	Distance on LiMa housing (D = 105mm) mm from OT
2.5	21.6	19.8
2.75	22.7	20.8
3	23.7	21.8
3.25	24.7	22.7
3.5	25.7	23.5
3.75	26.6	24.4
4th	27.6	25.2
4.25	28.4	26.0
4.5	29.2	26.8

Stroke 65mm connecting rod length 130 mm BK350, MM 175 (ES175), MM 250 (ES250) MM 175/1 (ES175 / 1), MM 250/1 (ES250 / 1) MM 175/2 (ES 175/2), MM 250/2 (ES 250/2, ETS 250) MM 250/3 (TS250), MM 250/4 (TS250 / 1) EM 250 (ETZ250), EM 251 (ETZ251), EM 301 (ETZ301)
ZZP in mm v.OT	ZZP in ° v.OT	Distance on LiMa housing (D = 105mm) mm from OT
2.5	20.3	18. 6
2.75	21.3	19.5
3	22.2	20.4
3.25	23.2	21.2
3.5	24.1	22.0
3.75	24.9	22.8
4th	25.8	23.6

Stroke 72mm connecting rod length 145 mm ES300
ZZP in mm v.OT	ZZP in ° v.OT	Distance on LiMa housing (D = 105mm) mm from OT
2.6	19.6	18.0
2.8	20.4	18.7
3.0	21.1	19.3
3.2	21.8	20.0
3.4	22.5	20.6

With the Rotax engine type 504, the speed-dependent ignition position is determined by the fixed position of two sensor coils in the LiMa. The indication of the relationship between the ignition position and the ignition angle is therefore purely informative.

Stroke 79.4 mm, connecting rod length 140 mm Rotax type 504 (MZ 500R)
ZZP in mm v.OT	ZZP in ° v.OT	ZZP in mm v.OT	ZZP in ° v.OT
0.03	2	2.2	17th
0.07	3	2.5	18th
0.12	4th	2.7	19th
0.2	5	3.0	20th
0.3	6th	3.3	21st
0.4	7th	3.7	22nd
0.5	8th	4.0	23
0.6	9	4.3	24
0.8	10	4.7	25th
0.9	11	5.1	26th
1.1	12th	5.5	27
1.3	13	5.9	28
1.5	14th	6.3	29
1.7	15th	6.7	30th
2.0	16	7.1	31

bibliography

[1]

Collective of authors: Repair manual for the MZ motorcycles ES125 and ES150

2nd edition, VEB Fachbuchverlag Leipzig, editorial deadline February 15, 1967

[2]

Neuber, Heinz; Müller, Karlheinz: How do I help myself? MZ motorcycles

1st edition, VEB Verlag Technik Berlin, 1981

3rd edition, VEB Verlag Technik Berlin, 1988 (ISBN 3-341-00472-6)

[3]

http://www.elweb.info/projekte/dieterwerner/AKKU1A1.pdf

http://www.elektrotec-berlin.de/download/de/A200dt.pdf

as well as further links that were no longer active in July 2008

[4]

Repair manual Type 348

Bombardier-Rotax GmbH, engine factory, Gunskirchen (Austria), edition 1988

[5]

Blocker, Joachim; Neyderek, Franz: Vehicle electrics

6th edited edition, transpress VEB Verlag für Verkehrwesen Berlin, 1988

[6]

Source: www.vision-batt.com

[7]

Repair manual for the MZ motorcycles ETZ125, ETZ150 and ETZ251

Fachbuchverlag Leipzig 1989 or reprint as 1st edition in Welz-Verlag Berlin 1998

[8th]

Repair manual (chassis) Saxon 500, Fun, Tour, Country, Silverstar

Motorrad- und Zweiradwerk GmbH, July 1995