Isuzu KB P190. Manual — part 253

ENGINE ELECTRICAL 6D – 11

RTW46DSH000301

7. Rotor

Assembly

1. Remove the rotor from front cover assembly.

Remove the front cover stator and rectifier.

RTW46DSH000701

8. Front Cover Assembly

1. Remove the front cover bearing retainer screws.
2. Remove the bearing.

RTW46DSH000801

9. Rear rotor bearing

• Re-use improper parts.

10. Rectifier

1. Disconnect the stator coil leads between each rectifier

by melting the solder connection.
Hold the lead wire between the solder and the rectifier
with a pair of long nose pliers.
This will prevent heat transfer and resultant damage to
the rectifier.

RTW46DSH000401

6D – 12 ENGINE ELECTRICAL

INSPECTION AND REPAIR

Make the necessary adjustments, repairs, and part replacement if excessive wear or damage is discovered during
inspection.

ROTOR ASSEMBLY

1. Inspect the slip ring faces for dirt and pitting.

Wipe away any dirt with a clean cloth soaked in
alcohol.

2. Measure the slip ring diameter.
Slip Ring Diameter

mm (in)

Standard Limit

RTW06DSH000101

31.6 (1.245)

30.6 (1.183)

If the slip ring diameter is less than the specified limit, the
slip rings must be replaced.

3. Measure the rotor coil resistance.

Rotor Coil Resistance at 20

°C (68°F) ohms

Standard 3.8

RTW46DSH001001

RTW46DSH001101

4. Check for continuity between the slip rings and the

rotor core or shaft.
If there is continuity, the entire rotor assmbly must be
replaced.

ENGINE ELECTRICAL 6D – 13

STATOR COIL ASSEMBLY

1. Check for continuity across the stator coils.

If there is no continuity, the stator coils must be
replaced.

Resistance Between The Terminal “N” and the Coil Ends
(Reference) ohms

Standard 0.1

066RY00022

2. Check for continuity between each stator coils and the

stator core.
If there is continuity, the stator coils must be replaced.

066RY00023

RTW46DSH004801

BRUSH

Measure the length of the brush. If abrasion has reduced
the brush length to less than 6.5 mm, the brush must be
replaced with a new one.
A wear line is inscribed in the brush. If the line is not
visible, the brush must be replaced.
Brush Length (Reference)

mm (in)

Standard Limit

25 (1.0)

6.5 (0.25)

RTW46DSH001201

Rectifier

Tester wire

E BAT

U, V, and WN

⊕

U, V, and WN

⊕

⊕

----- Conductivity

⊕

-----

No

conductivity

No

conductivity

-----

Conductivity -----

Negative

side diode check

Positive

side diode check

6D – 14 ENGINE ELECTRICAL

RECTIFIER ASSEMBLY

RTW46DSF000301

1. Voltmeter
2. Switch

1

3. DC regulated power supply
4. Lamp

2

5. Lamp

1

6. Switch

3

7. Switch

2

8. Pulse

generator

9. Output

signal

Test circuit

Refer to the judgment criteria shown in the Table below.
Carefully check Items 1~5. If all the items are OK, the IC
regulator is normal.

Circuit components

1

DC regulated power supply

0~20 volts variable with output of 1 ampere or more

2

Lamps (2)

12 volts, 1.4~3.4 watts

3

Switches (3)

-----

4

DC voltmeter

0~30 volts, 0.5 grade

5

Pulse generator (Oscillator)

5~30 volt output at a frequency of 1kHz

Judgment criteria

Lamp condition

No.

Switch

1

Switch

2

Switch

3

Voltmeter

reading

Lamp 1

Lamp 2

Remarks

1

ON OFF OFF

On

(dim)

ON

Initial excitation check

2

ON ON OFF

12V

On or

flashing

Full excitation check

3

ON ON OFF 16V

Off or

on (dim)

OFF

Lamp 1 off or dimly lit when the
voltmeter shows less than 12 volts or
16 volts

4

OFF ON OFF 12V

On or

flashing

Stator and brush separation check

5

ON ON ON 18V On

ON

Excess voltage check