Isuzu 4ja1, Workshop Manual

Page: 246 / 564

6D – 26 ENGINE ELECTRICAL
INSPECTION AND REPAIR
Make the necessary adjustments, repairs, and part replacement if excessive wear or damage is discovered during
inspection.
ARMATURE
1. Measure the commutator run-out.
Replace the commutator if the measured run-out
exceeds the specified limit.
Commutator Run-Out mm (in)
Standard Limit
0.05 (0.002) 0.2 (0.008)
RTW46DSH003501
2. Check the commutator mica segments for excessive
wear.
3. Measure the mica segment depth.
Mica Segment Depth
mm (in)
Standard Limit
0.5
∼
0.8 (0.020
∼
0.030)
0.2 (0.008)
065RY00025
If the mica segment depth is less than the standard but
more than the limit, the commutator may be reground.
If the mica segment depth is less than the limit, the
commutator must be replaced.
4. Measure the commutator outside diameter.
Commutator Outside Diameter
mm (in)
Standard Limit
36.5 (1.44) 35.5 (1.40)
If the measured outside diameter is less than the specified
limit, the commutator must be replaced.
065RY00026
RTW46DSH003601
5. Use a circuit tester to check the armature for
grounding.
1 Hold one probe of the circuit tester against the
commutator segment.
2 Hold the other circuit tester probe against the
armature core.
If the circuit tester indicates continuity, the armature is
grounded.
The armature must be replaced.