Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1714

6D3-14  STARTING AND CHARGING SYSTEM

7. To remove the pulley, mount an 8mm Allen key  in  the  vice

with the short end upwards, place a 24mm ring spanner on

the puley nut, position the internal hexagon of the rotor shaft

onto the Allen ken, loosen the nut and remove the pulley.

Note: the pulley has an integral boss which locks up against
the bearing,
therefore no thrust collar is provided.

8. Removing  the  rotor  assembly.  Remove  the  four  retaining

screws  from  the  drive  end  housing,  withdraw  the  rotor

complete with the bearing.

Note: the rotor must not be pressed from the drive end housing
using a press as 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.
9. Remove  the  drive  end  bearing  from  the  rotor  shaft  using  a

chuck  type  puler,  take  care  not  to  distort  the  fan  assembly

during this process.

10.Remove  the  slipring  end  bearing  using  the  same  meghod

as in 9.

Clean

Thoroughly clean all components except the rotor and stator
with an approved cleaning agent.  Ensure that all traced of oil
and dirt are removed. If an abrasive cleaner is used to remove
scale and paint from the housings take care not to abrade the
bearing and mounting spigot surfaces.  The rotor and stator
must be cleaned with compressed air only, the use of solvents
could cause damage to the insulating materials.

Inspection

1. Rectifier assembly

The following test equipment is required.
The recitifier assembly is not repairable and must be replaced
if a faulty diode is detected during inspection.

(a) Adiode tester where the  DC output at the test probes does

not  exceed  14  volts  or  in  the  case  of  AC  testers  12  volts

RMS.  This  is  to  ensue  that  when  inspection  rectifiers  fitted

with  zener  power  diodes  the  forward  and  reverse  checks

are completer  and  are  not  masked  by  the  diode  turning  on

due to the zener breakdown voltage.

(b) A  zenere  diode  tester  with  a  DC  output  in  excess  of  30

volts,  the  tester  should  also  incorporate  internal  current

limiting  set  to  5  Ma.  to  prevent  high  currents  during

inspection.

(c) Diodes  can  be  destroyed  during  service  due  to  high

temperature and overload, open circuits are usually a result

of excessive voltage.

STARTING AND CHARGING SYSTEM  6D3-15

Positive heatsink

8 diode

6 diode

H

G

Negative heatsink

C

B

A

Starpoint

F

E

B+Bolt

D

Diode connections

Stator connection

1.1

Power Diodes.

Apply the negative test probe of the diode tester or a
multimeter with a diode test feature to the positive heatsink and
the positive probe alternatevely to A,B,C, a low resistance
reading, or the forward voltage drop across the diode shoud be
obtained. Reverse the test probes, a high resistance reading or
a higher reverse voltage should be obtained.

Now connect the positive test probe to the negative heatsink
and the negative alternatively to D,E,F, a low resistance or
forward voltage drop across the diode should be obtained.
Reverse the test probes, a high resistance reading or a higher
reverse voltage should be obtained.

For 8 diode rectifier plates tests for G and H should be
included. When the reverse voltage test is done the applied
voltage should be less than 14 volts DC or 12 volts RMS for
AC testers.

1.2Zener Diode

The basic tests in 1.1 should be undertaken first before the
diode zener voltage is tested.  Diodes are grouped together
according to their zener voltag i.e. all diodes within a rectifier
must have the same zener voltage.

Connect the test probes as for the reverese test listed above
i.e. reverse biased apply the test voltage form the zener diode
tester (current limited to 5ma) and read to zener breakdown
voltage this should be a steady reading and not increase with
increased voltage from the tester.

6D3-16  STARTING AND CHARGING SYSTEM

Readings for Zener diode groups 011 to 042

Zener voltage at
5Ma.

Positive
diode

Negative
diode

Fordward
current Rating

17.8v-19.2v

011

012

25A

18.8v-20.2v

013

014

25A

19.8v-21.2v

015

016

25A

20.8v-22.2v

017

018

25A

21.8v-23.2v

019

020

25A

22.8v-24.2v

021

022

25A

17.8v-19.2v

031

032

35A

18.8v-20.2v

033

034

35A

19.8v-21.2v

035

036

35A

20.8v-22.2v

037

038

35A

21.8v-23.2v

039

040

35A

22.8v-24.2v

041

042

35A

Note: Diode number is stamped on the rear of the diode.

2. Stator

Inspect the stator insulation resistance to ground with an
insuation tester or a series test lamp up to 110 volts.
The insulation resistance must be greater than 1 megohm.
The winding reisistance is measured between phases using a
low reading ohmmeter designed for this purpose, the values
are given at the rear of this instruction.

3. Rotor

Inspect the rotor for insulation resistance to ground using an
insulation tester or a series test lamp up to 110 volts.
The insulation resistance must be grater than 1 megohm.
Measure the rotor resistance between the sliprings using an
ohmmeter or apply 12 volts across the sliprings and measure
the rotor current flow, then divide 12 by the measured current,
the results is the rotor resistance in ohms. values are given at
the rear of this instruction.

If the sliprings are worn or out of round they must be re-
machined to a minimum diameter or 26.7 mm and should have
a runout not exceeding 0.060mm.  If the slipring is below these
limits it must be replaced with a new one.

Warning; extreme care must be exercised when machining
the slipring as it is possible for the turning tool to foul the fan.

STARTING AND CHARGING SYSTEM  6D3-17

4. Replacing the brushes (inbuilt regulator)

Check the brushes for length, this is measured from the brush
holder to the end of the brush along it's centre line. Also
inspect for any sideways wear. If worn replace both brushes.
The minimum length is 3.8mm. Inspect the brush springs for
signs of corrosion or loss of tension or uneven tension.

Replacing the brushes, using a soldering iron apply heat to the
soldered joints on the rear of the brush holder of the regulator,
using a small lever prise up the retaining tabs to release the
brush lead and spring.   Thread the new brush lead up the
brush holder along with the spring, pull the lead through the
tabs until the brush is protruding 12mm from the holder.
Bend down the tabs and solder the brush lead taking care not
to allow the solder to run up the lead which will reduce
flexibility.  Use 60/40 resin cored solder.

5. Ball bearing

Please note the bearings used in this KCA generator are a high
tolerance type, only fully sealed bearings of the same
specification are to be used as replacements. It is
recommended that the bearings be replaced during the
reconditioning process to restore the unit to original
specification.

6. Regulator

The regulator can only be tested when fitted into an altenator.

Warning: do not reverse"S" and "L" connections or put 12
volt supply to "L" terminal, this connection must not be
used as a supply source other than to supply the
requirements of the warning lamp 2(watts).
Such action will destroy the regulator warning lamp
circuit.

For test voltages refer to Generator output testing section.
See also additional information on regulator function earlier in
this instruction.