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