SECTION 6D1-1 CHARGING SYSTEM - V6 ENGINE &

V6 SUPERCHARGED

CAUTION:

This vehicle will be equipped with a Supplemental Restraint System (SRS). A SRS will

consist of either seat belt pre-tensio ners and a driver’s side air bag , or seat belt pre-

tensioners and a driver’s and front passenger’s side air bags. Refer to CAUTIONS,

Section 12M, before performing any service operation on or around SRS

components, the steering mechanism or wiring. Failure to follow the CAUTIONS

could result in SRS deplo yment, resulting in possible p ersonal injury or unnecessary

SRS system repairs.

CAUTION:

This vehicle may be equipped with LPG (Liquefied Petroleum Gas). In the interests of

safety, the LPG fuel system should be isolated by turning 'OFF' the manual service

valve and then draining the LPG serv ice lines, before any service w ork is carried out

on the vehicle. Refer to the LPG leaflet included with the Owner's Handbook for

details or LPG Section 2 for more specific servicing information.

1. GENERAL DESCRIPTI ON

On VT Series Models with V6 engine, a new Bosch KC-A Compact 100 amp generator is fitted. The KC-A generator

can be identified by its external appearance in that it does not have an external cooling fan.

The generator is a 3 phase type, incorporating a rotor having 6 pole pairs fitted with 2 cooling fans, one on the drive

end and the other on the slip ring end. Rotor current is conveyed to the rotor winding by a pair of slip rings and

carbon brushes via the voltage regulator. The rotor is supported by ball bearings in both the drive and slip ring end

housings. Surrounding the rotor is a stator, which is of a three phase star connected output winding construction on

a ring shaped lamination pack.

The output of the stator winding is rectified by six diodes which are contained within the slip ring end housing.

Excitation current is supplied to the rotor field coil via the voltage regulator, brushes and slip rings. The electronic

voltage regulator requires no adjustment in service.

The generator has four external connections; the ‘B+’ lead to the battery positive terminal, the ‘L’ lead to the

generator warning lamp (max. 2 watts), the ‘S’ lead for battery voltage sensing and an earth connection, refer Fig.

6D1-1-1.

Fig. 6D1-1-2 shows an exploded view of the 100 amp generator.

Techline

Figure 6D1-1-1

Figure 6D1-1-2

1 Nut 11 Stator 20 Slip Ring End Housing

2 Lock Washer 12 Slip Ring End Bearing Support

Ring 21 Terminal Cover Bush

3 Drive Pulley 13 Rectifier Attaching Screws 22 Flat Washer

4 Bearing Retaining Plate Screw (4) 14 B+ Terminal Bolt 23 B+ Terminal Retaining Nut

5 Through Bolt (4) 15 Rectifier Assembly 24 Suppressor

6 Drive End Housing 16 Mica Insulating Washer 25 Suppressor Attaching

Screw

7 Drive End Bearing 17 Insulating Washer 26 Regulator and Brush

Screws

8 Bearing Retaining Plate 18 Spacer 27 Regulator and Brush

Assembly

9 Rotor 19 Slip Ring End Housing Lug

Sleeve

10 Slip Ring End Bearing

1.1 OPERATION

With the ignition switch turned to the ON position, current is supplied via the warning lamp to the ‘L’ terminal of the

regulator. Base current from the regulator hybrid circuit is fed to the transistor T15 which turns ON. Current then

flows from the B+ terminal through the rotor winding via the regulator brushes and the collector emitter junction of

transistor T15 to earth, completing the circuit.

The current in the rotor causes a magnetic field between adjacent poles to be created, this field is rotated and cuts

the windings of the stator at right angles inducing a voltage into them. As the speed is increased, this induced

voltage increases and results in current being rectified in the 3 phase diode bridge and supplied as DC to the B+

output and hence to the battery. When the voltage at the B+ terminal to the battery reaches approximately 14.2

volts, the ‘S’ terminal which is monitoring this voltage, turns the regulator hybrid circuit base current to the transistor

T15 off, removing rotor current. This results in a decrease in output voltage to below the regulating voltage,

transistor T15 base current is turned back on and the whole cycle is repeated very rapidly. Diode D38 protects the

transistor T15 and the regulator against the back voltage developed across the rotor winding when transistor T15

tu rns off.

Should a situation arise where the main B+ cable or battery sense wire (terminal S) become disconnected or have a

high resistance, the regulator will limit the output voltage to a safe level (backup mode), approximately 1-3 volts

above the regulators normal setting.

When the ignition switch is turned on and the engine is not running, the current to the rotor is reduced by switching it

on and off at a 50% duty cycle (active standby mode), the frequency is approximately 4kHz and may be audible at

times (this is normal). Once the engine is started, normal regulation commences.

Should the warning lamp fail, the generator will self excite by deriving a small current from the phase connection

allowing the voltage to build up to regulating level.

NOTE:

No rotor winding current will flow when the engine is cranking.

The regulator incorporates internal diagnostics which will illuminate the warning lamp as a result of fault conditions

in the generator and/or external circuitry.

These conditions include:

1. An open circuit in the regulator battery sensing wire (S terminal).

2. An open circuit or excessive voltage drop in the B+ cable.

3. An open circuit in the generator phase connection.

4. Overcharging of the battery.

5. Regulator output stage short circuit.

6. Open circuit in the rotor winding.

The regulator compares the voltage at the B+ terminal with the voltage sensed at the S terminal connected to the

battery positive. If the voltage differential exceeds a predetermined threshold, the regulator will operate in backup

mode to limit the output voltage to a safe level. The warning lamp will remain illuminated as long as the fault

conditions prevail.

Sources of high resistance which will trigger the warning lamp are:

1. Poor contact in the wiring harness connectors.

2. Poor contact between the rectifier and the regulator.

3. High resistance in the fusible link assembly or battery terminals and cables.

Figure 6D1-1-3

2. MI NOR SERVICE OPERATIONS

2.1 SAFETY PRECAUTIONS

Since the generator and voltage regulator are designed for use only on a negative earth system, the following

precautions must be observed. Failure to observe these precautions will result in serious damage to the generator.

1. When installing a battery, first fit positive (+) cable to battery positive (+) terminal and then fit negative (-) cable

to battery negative (-) terminal.

2. When a slave battery is utilised for starting purposes, ensure both batteries are connected in parallel, ie.

positive terminals together and negative terminals together.

3. When charging battery, disconnect both battery cables, thus isolating generator from battery and external

charging equipment.

4. The generator must not be operated on open circuit (this is without battery in circuit), and battery must not be

disconnected while the generator is running.

5. Do not attempt to polarise generator.

6. Always ensure that generator warning lamp glows when ignition switch is turned to ‘ON’ position.

NOTE:

As this circuit is related to and assists in the excitation of the rotor field windings, do not proceed until any faults in

the generator warning lamp circuit have been rectified. Ensure the warning lamp wattage does not exceed 2 watts.

7. The ‘L’ terminal of generator should never be connected to battery or ignition circuit (12 Volts), as this will

damage generator warning lamp circuit.

8. Some battery powered timing lights can produce high transient voltages when connected or disconnected. Only

disconnect or connect timing lights when the engine is switched off.

2.2 MAINTENANCE AND ON VEHICLE TESTING

At regular intervals, inspect the terminals of the generator for corrosion, loose connectors and the wiring for

damaged insulation. Check the mounting bolts for tightness, check the drive belt for alignment and wear and the

drive pulley for damage. The drive belt adjustment for the engine ancillaries, such as the generator and water pump

etc., is provided by a spring loaded tensioner. The drive belt therefore, does not require any regular adjustment.

LUBRICATION

The ball bearings supporting the rotor shaft are pre-lubricated and sealed, therefore no lubrication is possible during

service.

The bearings used in this generator are high tolerance type. If the bearings are removed during the generator

disassembly, new bearings must be installed to restore the generator to original specification.

NOTE:

Two special tools (Bosch tool numbers 9881 066 600 and 9881 066 601) are available to ensure correct dismantling

and assembly procedure of the rotor bearings. It is extremely difficult to remove the bearings without damaging the

rotor fans. The assembly tool ensures that the bearings are installed correctly and are properly aligned, which will

ensure long service life.

TESTING THE GENERATOR OUTPUT AND VOLTAGE REGULATOR

TESTING PREREQUISITES

Before testing the generator output, make certain that the generator circuit is thoroughly checked for loose or dirty

connections. The generator must always be connected to the battery during testing, otherwise damage to the

diodes could result.

The battery should be fully charged. Test the specific gravity of the individual cells. The readings should be within

10 points of each other. It is recommended that the average specific gravity should be 1.260 or higher.

A load test should be carried out to determine the ability of the battery to supply and accept current. This is a good

indicator as to the general condition of the battery. Refer to Section 12A BATTERY AND CABLES for details of

battery testing.

The generator warning light, in addition to indicating that the generator is charging, is also necessary for initial field

excitation.

Inspect drive belt and tensioner markings to determine if belt is within operating limits. Replace belt if it is

excessively worn or outside tensioner’s operating range, refer to Section 6A1 ENGINE MECHANICAL - V6

ENGINE.

TESTING GENERATOR OUTPUT

REGULATING VOLTAGE TEST ON THE VEHICLE

1. Ensure that all the electrical equipment is

turned OFF, and the ignition switch is in the

OFF position.

2. Disconnect battery earth cable at battery.

3. Disconnect the generator positive lead (red

wire) from the ‘B+’ generator terminal.

4. Connect the positive lead of an ammeter (0 -

100 Amp s cale) to the generator ‘B+’ terminal,

and the negative ammeter lead to the

disconnected generator positive lead (red

wire).

5. Connect positive lead of a voltmeter (0 - 20

Volt scale minimum) to the generator ‘B+’

terminal, and negative voltmeter lead to a

good earth connection on the generator

housing.

CAUTION:

Insulate the generator positive lead (red wire)

terminal to prevent contact with any metal part

of the vehicle. If the terminal is earthed,

damage to the charging circuit will result when

the battery is reconnected.

6. Reconnect the battery earth cable. Fit a

loading device across battery term inals, i.e. an

adjustable carbon pile.

NOTE:

Loading device must have a minimum power

consumption of 1000 watts.

7. Note and record the voltmeter reading before

the engine. This reading s hould inc reas e when

the engine is running, indicating generator

output.

8. Start engine, raise RPM and adjust load

(ammeter reading) to that nominated in the

following chart. Check generator output

(voltmeter reading) against specification.

Figure 6D1-1-4

ENGINE RPM

LOAD

VOLTMETER READING

1275

5 - 10 Amps

14.2 - 14.6 Volts

LOAD REGULATION TEST

With the voltmeter, ammeter and carbon pile

connected as in previous test, increase engine

speed to 1900 RPM (approx imately 6000 generator

RPM) and increas e load to approximately 90 amps

(90% of full output). A decrease in the regulating

voltage should not exceed 0.5 volts of the r eadings

obtained in the previous test.

If the decrease in the regulating voltage is greater

than 0.5 volts, the regulator is defective and must

be replaced.

GENERATOR OUTPUT TEST AT FULL LOAD

With the voltmeter, ammeter and carbon pile connected as in previous tests, increase engine speed to 1900 RPM

(approximately 6000 generator RPM) and increase load until the generator output voltage drops to 13.5 volts and

note ammeter reading.

Full output (100 amps) should be obtained under these conditions. It may be necessary to adjust the throttle so as

to maintain the desired engine speed.

NOTE:

Keep the time for this test to a minimum so as to avoid undue heating and high engine speeds.

If the generator does not provide rated output, it should be disassembled and inspected for faults, refer to

3.1 GENERATOR in this Section.

CAUTION:

On completion of the generator output testing, to prevent excessive battery discharge occurring, the

engine should be returned to idle speed and the loading device disconnected from battery terminals.

9. Disconnect the battery earth cable at battery. Remove the volt and ammeters, then reconnect the generator

positive lead (red wire) to the generator ‘B+’ terminal. Reconnect the battery earth cable to the battery.

CHARGING CIRCUIT VOLTAGE DROP TEST

With normal connections made at generator, charging circuit can be checked for voltage drop as follows:

1. Connect a low range voltmeter between generator positive terminal and battery positive post.

2. Switch on headlamps, start engine and increase engine speed to approximately 2500 rpm and note voltmeter

reading.

3. Reduce engine speed and transfer voltmeter connections, negative to generator housing and positive to battery

negative post. Increase engine speed to approximately 2500 rpm and again note voltmeter reading.

4. If readings exceed 0.5 volts on positive side and 0.25 volts on negative side, there is a high resistance in

charging circuit which must be traced and corrected.

5. Reduce engine speed and transfer voltmeter connections, negative to generator body and positive to battery

negative post. Increase engine speed to approximately 2500 rpm and again note voltmeter reading.

6. If readings exceed 0.5 volts on positive side and 0.25 volts on negative side, there is a high resistance in

charging circuit which must be traced and corrected.

3. MAJOR SERVICE OPERATIONS

3.1 GENERATOR

REMOVE

1. Disconnect battery earth lead.

2. Remove four dome nuts securing the engine

dress cover assembly to the intake manifold

studs, lift off and remove the cover assembly.

Refer to Fig. 6D1-1-5 for V6 ENGINE and Fig.

6D1-1-6 for SUPERCHARGED V6 ENGINE.

Figure 6D1-1-5

Figure 6D1-1-6

Techline

3. Using a 15 mm ring spanner on drive belt

tensioner pulley pivot bolt, rotate tensioner

pulley assembly anti-clockwise and remove

drive belt from generator drive pulley. Release

drive belt tensioner.

Figure 6D1-1-7

4. Pull back battery harness cap from ‘B+’

term inal, r emove nut, washer and pos itive lead

(red wire).

Figure 6D1-1-8

5. Remove generator brace to generator

attaching bolt and loosen brace to engine

bracket attaching bolt.

Figure 6D1-1-9

6. Remove generator to drive belt tensioner

bracket upper bolt and loosen lower bolt.

Figure 6D1-1-10

7. Swing back generator away from the intake

manifold and remove battery harness

connector from regulator and brush assembly

terminal block by depressing connector

retainer and pulling connector from generator.

8. Remove generator to drive belt tensioner

bracket lower bolt and remove generator

assembly.

Figure 6D1-1-11

REINSTALL

1. Assemble generator to drive belt tensioner

bracket and install lower mounting bolt, leaving

it loose. Refer to Fig. 6D1-1-12 for

SUPERCHARGED V6 ENGINE and Fig. 6D1-1-

13 for NON-SUPERCHARGED V6 ENGINE.

2. Install battery harness connector into

generator’s regular and brush assembly

terminal block, ensuring that connector’s

retainer locks into place.

3. Swing generator up toward intake manifold and

install generator to drive belt tensioner bracket

attaching bolt.

4. Install generator brace onto generator housing

and install attaching bolt.

GENERATOR TO DRIVE BELT

TENSIONER LOWER 40 - 50

ATTACHING BOLT Nm

TORQUE SPECIFICATION

GENERATOR TO DRIVE BELT

TENSIONER UPPER 40 - 50

ATTACHING BOLT Nm

TORQUE SPECIFICATION

GENERATOR BRACE TO

GENERATOR ATTACHING BOLT 20 - 30 Nm

TORQUE SPECIFICATION

GENERATOR BRACE TO ENGINE

BRACKET ATTACHING BOLT 20 - 30 Nm

TORQUE SPECIFICATION

Figure 6D1-1-12

5. Install battery harness positive lead (red wire),

washer and nut on ‘B+’ terminal. Tighten nut

to the correct torque specification. Refit cap

over ‘B+’ terminal.

‘B+’ TERMINAL NUT TORQUE

SPECIFICATION 5 - 12

6. W ith aid of a 15 mm ring spanner , rotate drive

belt tensioner anti-clockwise and fit drive belt

to generator drive pulley. Release tensioner

and ensure that drive belt ribs are correctly

installed into all accessory drive pulleys and

crankshaft balancer drive belt grooves.

Figure 6D1-1-13

7. Reconnect battery earth lead.

8. Start engine and check generator warning

lamp operation, drive belt alignment,

generator output and voltage regulator

operation.

9. Reinstall engine dress cover to intake

manifold, ensuring that stud grommets in the

dress cover remain in place. Install dome nuts

and tighten to the correct torque

specifications.

ENGINE DRESS COVER TO

INTAKE MANIFOLD DOME NUT

TORQUE SPECIFICATION 4 - 6 Nm

DISASSEMBLE

The following precautions must be noted before

attempting to disassemble the generator and

checking for faulty components.

a. When testing the rectifier diodes with an

AC type tester, the RMS output must not

exceed 12.0 volts. It is recommended that

the stator should be disconnected before

testing the diodes.

b. When testing the diodes breakdown

voltage, all diodes should have the same

zener voltage.

c. Insulation tests on the rotor and stator

should use a voltage not exceeding 110 V

for a s eries tes t lam p. T he rectif ier m us t be

disconnected from the stator prior to

testing.

d. Due to the very low resistance value of the

stator winding, it may not be possible to

obtain accurate readings using a

conventional ohmmeter.

1. Mark relative positions of slip ring end

housing, stator frame and drive end housing

using a permanent marking pen.

Figure 6D1-1-12

2. Remove two screws securing regulator and

brush assembly to slip ring end housing.

Holding the term inal block of the regulator and

brush assembly, tilt the assembly up from the

slip ring end housing and then lift out, taking

care not to damage the brushes.

NOTE:

The regulator must not removed with the ‘B+’

supply cable connected, as dam age to the rectified

‘B+’ rail can result.

Figure 6D1-1-13

3. Remove four through bolts.

4. Carefully separate the slip ring end housing

and stator (as an assembly) from rotor and

drive end housing, tak ing care not to put strain

on the stator wires.

Figure 6D1-1-14

5. To remove the drive pulley, mount an 8 mm

Allen key in a vice with the long end pointing

out from the side of the vice.

Place a deep 24 mm socket with external hex

(commercially available) onto the pulley

attaching nut and place a suitable size

spanner over socket hex.

As an alternative, use a deep 24 mm socket

and weld a suitable length bar to the side of

the socket to act as a lever.

Position drive end housing and rotor ass embly

with the internal hexagon of the rotor shaft

onto the Allen key.

Loosen drive pulley attaching nut. Remove

drive end housing from Allen key .

NOTE:

Under no circums tances is the rotor to be m ounted

in the vice as the rotor and or cooling fans will be

damaged. Figure 6D1-1-15

6. Remove drive pulley attaching nut, lock

washer and drive pulley.

Figure 6D1-1-16

7. Remove four screws securing the bearing

retaining plate to drive end housing.

8. Push the rotor shaf t and fr ont bearing fr om the

drive end housing.

NOTE:

The rotor must not be pressed from the drive end

housing.

If the rotor is pressed out, the bearing retaining

plate and drive end housing will be damaged or

distorted. Parts removed in this way MUST be

replaced if the integrity of the generator is to be

maintained.

Figure 6D1-1-17

9. Using the drive end housing bearing removal

tool (Bosch tool 9981 066 601), remove drive

end bearing from rotor shaft.

NOTE:

This process will damage the bearing retaining

plate and must be replaced. As the bearings are

fine tolerance, high speed, noiseless design they

must also be replaced. (drive end bearing No.

9900 069 006)

Figure 6D1-1-18

10. Using the puller, remove slip ring end bearing

from rotor shaft, taking care not to distort the

rear fan during the process.

Remove retaining plate from rotor shaft.

Figure 6D1-1-19

11. Remove nut, wave washer, flat washer and

insulating washer from the ‘B+’ terminal bolt.

12. Remove suppressor lead connection from

rectifier ‘+’ terminal.

13. Remove three screws attaching rectifier

assembly to slip ring end housing. Remove the

stator and rectifier as an assembly. Remove

spacer and mica insulating washer from ‘B+’

terminal bolt.

Remove second mica insulating washer from

beneath rectifier positive heat sink . (Washer

may be adhered to boss on inside of slip ring

end housing).

NOTE:

Discard the two mica insulating washers as new

washers and heatsink compound must be used on

reassembly.

Figure 6D1-1-20

14. Separate stator from rectifier assembly by

unsoldering the three stator windings to

rectifier connections.

CAUTION:

Use only as much heat as required to melt the

solder. Excessive heat may damage the diodes.

15. To disconnect the stator from the rectifier

assembly, grasp the stator wires close to the

wire loop with a pair of pointed nose pliers.

Heat the joint with a soldering iron and when

the solder at this point starts to melt, apply a

slight twisting motion to the wires, then pull

upwards to release.

NOTE:

The rectifier assembly is serviced as an assembly

only. Individual replacement parts are not available.

Figure 6D1-1-21

CLEANING AND INSPECTION

With generator completely disassembled,

components should be cleaned and inspected.

Wash all components except stator, rotor, rectifier

and regulator in a suitable cleaning solvent.

Carefully clean rotor and stator with compressed

air.

CAUTION:

Do not clean stator or rotor windings with the

cleaning solvent or damage to the insulation

could result.

WARNING:

CLEAN ALL PARTS OTHER THAN THOSE

PREVIOUSLY NOMINATED USING A NON

VOLATILE OR LOW INFLAMMABLE AGENT IN

A WELL VENTILATED AREA.

IT IS IMPORTANT THAT ALL PARTS ARE

THOROUGHLY DRIED BEFORE ASSEMBLY,

TAKING CARE NOT TO BREATH IN ANY

VAPOURS.

OBSERVE THE SAFETY REGULATIONS AND

PRECAUTIONS ISSUED BY THE

MANUFACTURER OF THE CLEANING AGENT

IN USE.

COMPONENT CHECKING

BRUSH GEAR

Check the length of the brushes protruding from

the regulator brush holder. This is measured from

the brush holder to the end of the brush, along its

centre line.

MINIMUM BRUSH LENGTH 3.8 mm

If brush length is less than specified, replace

brushes as follows:

1. Unsolder brush leads from regulator brush

holder connections and bend back the

retaining lugs. Remove brushes and springs.

2. Inspect brush springs for discolouration,

breakage, corrosion or loss/uneven tension. If

any of these condition exists, replace springs.

3. Ensure that insulating sleeves are fitted over

new brush leads. Install brush springs over

brush leads. Thread new brush leads up br us h

holder along with springs, pull the leads

through the tabs until the brush is protruding

12 mm from the holder. Bend down the tabs

and solder the brush leads to the regulator

connections. Take care not to allow the solder

to run up the lead which would reduce its

flexibility.

4. Check that brushes m ove smoothly in and out

of holder by pushing on end of brushes, and

then releasing.

Figure 6D1-1-22

DIODES

NOTE:

The rectifier assem bly is not repairable and should

be replaced if any diodes proves to be faulty.

The following commercially available test

equipment is essential for correctly testing the

diodes within the rectifier assembly.

A. A diode tester or multimeter with a diode test

feature where the DC output at the test pr obes

does not exceed 14 volts , or in the c ase of AC

testers, 12 volts RMS.

This is necessary so as to ensure that when

testing the diodes, the forward and reverse

voltage checks are completed and are not

masked by the diode turning on due to zener

breakdown voltage.

B. A zener diode tester with a DC output in

excess of 30 volts. The tester should also

incorporate internal current limiting set to five

mA to prevent high currents during testing.

1. Attach negative test probe of diode tester or

multimeter with diode test function to the

positive heatsink of the rectifier assembly and

the positive probe alternatively to positive

diode connections A, B and C shown in Fig.

6D1-1-23.

A low resistance reading, or the forward

voltage drop across the diode should be

obtained.

Reverse probe connections and repeat test to

check that current is passed in one direction

only (high res istance r eading or higher revers e

voltage should be obtained).

Figure 6D1-1-23

2. Repeat procedure on negative heatsink by

attaching positive test probe to the negative

heatsink and the negative probe alternatively

to negative diode connections D, E and F

shown in Fig. 6D1-1-24.

A low resistance reading, or the forward

voltage drop across the diode should be

obtained.

Reverse probe connections and repeat test to

check that current is passed in one direction

only (high res istance r eading or higher revers e

voltage should be obtained).

NOTE:

In steps 1 and 2, ensure that the reverse voltage

applied is less than 14 volts DC, or 12 volts RMS

when using an AC tester.

Figure 6D1-1-24

3. Ensure that steps 1 and 2 are carried out

before the diodes zener voltage is tested. The

diodes are grouped together according to their

zener voltage, ie. all diodes within a rectifier

must have the same zener voltage.

To identify the zener voltage of the diodes,

refer to the numbers stam ped into the base of

each diode and to the following chart.

Figure 6D1-1-25

Diode Zener

Voltage

at 5mA

Positive

Diode

Number

Negative

Diode

Number

Forward

Current

Rating

17.8 - 19.2 031 032 35A

18.8 - 20.2 033 034 35A

19.8 - 21.2 035 036 35A

20.8 - 22.2 037 038 35A

21.8 - 23.2 038 040 35A

22.8 - 24.2 041 042 35A

4. To test the positive diode zener voltage,

connect the positive lead of the tester to the

positive heat sink and the negative lead to

diode connections A, B and C, refer Fig. 6D1-

1-23 (reverse bias of the diode) . Apply the test

voltage from the zener diode tester (current

limited to five mA) and read zener breakdown

voltage.

The voltage should be a steady reading and

not increase with increased voltage from the

tester.

NOTE:

The recommended zener tester is: Durst model

600 with five mA test current (Bosch approved).

5. Repeat step 4 to test the negative diode zener

voltage but with the tester’s negative lead

attached to the negative heat sink and the

positive lead to diode connections D, E and F

in turn, refer to Fig. 6D1-1-24.

ROTOR

INSULATION TEST

Using an insulation test er, or a series tes t lam p (up

to 110 V), check insulation between slip rings and

rotor core or shaft. Test light should not glow or

insulation tester should indicate an open circuit

(greater than 1 Megohm). If an open circuit does

not exist replace rotor.

Figure 6D1-1-26

OPEN CIRCUIT TEST

Connect ohmmeter probes across slip rings and

measure resistance of rotor windings.

Rotor winding resistance values are given in the

following chart.

NOTE:

If the resistance of the rotor winding is not to

specification, replace the rotor.

STATOR WINDING RESISTANCE 2.47 - 2.73

@ 20 DEGRESS C OHM

Figure 6D1-1-27

SLIP RINGS

Check slip rings for wear or damage. If the slip

rings are worn or out-of-round, they must be

machined to the minimum diameter specified as

follows and should have a run-out not exceeding

the following specification.

If the slip ring is below these limits, the rotor must

be replaced.

WARNING:

Extreme care must be exercised when

machining t he slip rings as it is po ssible f or t he

turning tool to foul the rotor’s rear cooling fan.

SLIP RING MINIMUM DIAMETER 26.7 mm

SLIP RING MAXIMUM OUT-OF-

ROUND 0.06

BEARINGS

The bearings used in this generator are a high

tolerance type. Only genuine replacem ent bearings

are to be used. It is recommended that the

bearings be replaced during the reconditioning

process to restore the generator to original

specification.

STATOR

INSULATION TEST

Connect a powered test lamp (up to 40 V) or an

ohmmeter between any stator lead and stator

frame. If test lamp glows or ohmmeter reading is

low indicating that an open circuit does not exist,

replace stator.

Figure 6D1-1-28

OPEN CIRCUIT TEST

1. Connect ohmmeter to any two stator leads.

Ohmmeter should not register any significant

resistance.

2. Repeat test on remaining stator leads. If

resistances are high, replace the stator.

The stator winding resistance is given in the

following chart.

STATOR WINDING RESISTANCE 0.058 - 0.063

@ 20 DEGRESS C OHMS

Figure 6D1-1-29

REASSEMBLE

Refer to Figure 6D1-1-2 for identification of

components

NOTE:

Special assembly tool (Bosch tool 9981 066 600)

fits both ballraces at one operation which reduces

noise and provides extended lifetime.

1. Attach new Drive End Bearing into Drive End

Housing with bearing plate. Tighten retaining

screws to the correct torque specification.

DRIVE END HOUSING BEARING

PLATE RETAINING SCREW 2.1 - 3.0 Nm

TORQUE SPECIFICATION

2. Insert new Slip Ring Bearing into recess in

Bearing Assembly Fixture. (Bosch tool 9981

066 600)

3. Insert Rotor into Bearing Assembly Fixture so

that rotor shaft at Slip Ring end is seated in

Slip Ring Bearing.

4. Place Drive End Housing onto Bearing

Assembly Fixture.

5. Insert mandrel into Drive End Housing and

press bearings into position.

Figure 6D1-1-30

6. Assem ble drive pulley, washer and nut to rotor

shaft.

Techline

7. Mount an 8 mm Allen key in a vice with the

long end pointing out from the side of the vice.

Place socket used for pulley nut removal onto

nut. Position drive end housing with the

internal hexagon of the rotor shaft onto the

Allen key.

Tighten drive pulley attaching nut. to the

correct torque specification.

DRIVE PULLEY ATTACHING NUT 54 - 68

TORQUE SPECIFICATION Nm

IMPORTANT:

Under no circums tances is the rotor to be m ounted

in the vice as the rotor and or cooling fans will be

damaged.

Figure 6D1-1-32

8. Inspect the slip ring end bearing support ring

for signs of damage, especially cracks. If in

any doubt replace the ring by pressing it into

the slip ring end housing by hand. DO NOT

USE EXCESSIVE FORCE.

NOTE:

The slip ring end bearing support ring will only

locate correc tly into the slip ring end housing in one

location, i.e. with the long tang on its outer diam eter

locating into the mating slot in the slip ring end

housing.

9. Apply heatsink com pound to both sides of new

rectifier positive heatsink mica washers.

Assemble mica washers to positive heatsink

with washer having largest hole fitted over the

B+ terminal bolt. The other mica washer is

fitted on the positive heats ink, around the hole

for the retaining screw.

10. Install spacer over B+ terminal bolt and

assemble rectifier into slip ring end housing.

Assemble insulating, flat, wave washers and

nut to B+ terminal, leaving nut finger tight.

Figure 6D1-1-33

11. Install and tighten rectifier retaining screws to

the correct torque specification.

RECTIFIER RETAINING SCREW

TORQUE SPECIFICATION 1.6 - 2.3

Tighten B+ terminal nut to the correct torque

specification.

B+ TERMINAL NUT TORQUE

SPECIFICATION 7.5 - 8.5

12. To refit the stator, ensure that the mating

surfaces of the stator frame, drive end and slip

ring end housings are clean and free from

damage.

Fit the stator into the slip ring end housing,

noting the correct lead positioning. Fit the

stator leads into the wire loops in the rectifier.

Using a pair of pointed nose pliers, squeeze

the loops to retain the stator leads prior to

soldering. Solder the leads into position using

60/60 resin cored solder.

Once completed, ensure the leads will clear

the internal fan when the rotor is assembled

into the stator.

13. Assem ble rotor and dr ive end housing into the

stator and slip ring end plate assembly,

aligning marks made during disassembly.

14. Reinstall through bolts and tighten evenly, and

to the correct torque specification.

THROUGH BOLT TORQUE

SPECIFICATION 3.8 - 5.5

NOTE:

Ensure that the slip ring housing and drive end

housing are seated squarely on the stator frame.

This ensur es that the air gap between the rotor and

stator windings is equal at all points.

15. Reinstall the regulator and brush assembly to

the slip ring end housing, ensuring that the

regulator engages with the spring connectors

on the rectifier. Ensure the brushes are

located correctly onto the slip rings.

Install the regulator and brush assembly

securing screws and tighten to the correct

torque specification.

REGULATOR AND BRUSH

ASSEMBLY SECURING SCREW

TORQUE SPECIFICATION 1.6 - 2.3 Nm

16. Reconnect suppressor lead to rectifier ‘+’

terminal.

4. DIAGNOSIS

1. UNDERCHARGED BATTERY

a. Defective battery

b. Loose connection in charging system

c. Corroded connections in charging circuit

d. Defective wiring

e. Faulty generator

f. Faulty voltage regulator

2. OVERCHARGED BATTERY

a. Shorted battery cell

b. Faulty voltage regulator

c. Short circuit in rotor winding

d. Voltage drop in sense wire

3. FAULTY INDICATOR LIGHT OPERATION

(LIGHT DOES NOT GLOW)

a. Burnt out bulb

b. Defective bulb socket

c. Defective wiring

d. Defective rectifier

e. Defective regulator

4. FAULTY INDICATOR LIGHT OPERATION

(LIGHT REMAINS ON)

a. Negative diode failure

b. Defective voltage regulator

c. Faulty generator

d. ‘B+’ cable off or broken

e. ‘S’ cable off or broken

f. Battery overcharged

g. Open circuit in rotor winding

5. NOISY GENERATOR OPERATION

a. Normal magnetic hum

b. Badly discharged battery

c. Generator mounting brackets loose or bolts loose

d. Worn or frayed drive belt

e. Worn bearings

f. Loose drive pulley attaching nut

g. Open or shorted diodes

h. Open or shorted stator winding

5. SPECIFICATIONS

Earth Polarity Negative

Nominal Voltage 12 V

Nominal Output 100 Amps

Stator Phases 3

Stator Winding Connections Star

Number Of Rotor Poles 12

Resistance of Rotor Winding ohms @ 20°C 2.47 - 2.73 Ω

Resistance of Stator Winding ohms @ 20°C 0.058 - 0.063 Ω

Voltage Regulator Setting 14.2 - 14.6 V

Brush Length (measured in brush holder) 12 mm (new), 3.8 mm (min)

6. TORQUE WRENCH SPECIFI CATIONS

Through Bolts 3.8 - 5.5

Drive End Housing Bearing Retaining

Plate Screws 2.1 - 3.0

Drive Pulley Attaching Nut 54 - 68

Regulator and Brush Assembly

Securing Screws 1.6 - 2.3

‘B+’ Terminal Nut 7.5 - 8.5

Battery Harness Terminal to ‘B+’

Terminal Nut 5 - 12

Rectifier Retaining Screw 1.6 - 2.3

Capacitor Fixing Screw 1.5 - 2.2

Generator to Support and Brace Mounting

Bolt 20 - 34

Generator to Drive Belt Tensioner

Bracket Mounting Bolt 20 - 34

7. SPECIAL TOOLS

TOOL NO. REF IN TEXT TOOL DESCRIPTION COMMENTS

9981 066 600 BEARING ASSEMBLY FIXTURE

9981 066 601 ROTOR BEARING REMOVAL TOOL