TM 55-6115-491-40
Table 4-1. Troubleshooting (Sheet 3 of 3)
TROUBLE
PROBABLE CAUSE
REMEDY
Excessive sparking at brushes
Exciter armature shorted
Replace rotor assembly.
Excessive commutator bar
Turn commutator on lathe.
Variation
No PM generator output
Permanent magnet rotor demagnetized
Recharge permanent magnet rotor.
Permanent magnet stator open or
Replace permanent magnet stator.
shorted
PM generator output low
One or more diodes defective
Check output with oscilloscope to
ascertain diode failure. Replace
Page 63
defective diodes.
4-9
