Field Coil; Brush - Komatsu 4D98 Series Shop Manual

9. Startim
Motor
(2) Field coil
a) Field coil continuity and earth tests
Test type Measurement point
Normal
Abnormal (cause)
Continuity test Across field coils Yes None (open circuit)
Earth test Between commutator
II None II
Yes (short-circuiting)
and voke
Replace if needed.
(Field coil continuity test)
(Field coil insulation test)
(3)
4
Brush
Check wear of the brush and the brush spring force.
18
Wear limit
(Wear limit for brush)
Spring balance
Piece of ClOth
(Measuring brush spring force)
9-25