Test rectifier bridge assembly (21).
Connect multimeter from grounded heat
sink (55) to diode terminal (56) and note
Reverse multimeter leads or reverse meter
polarity and again note resistance reading.
At one polarity, resistance reading should
be low and at the other polarity, resistance
reading should be very high, if diode is
good. If diode is faulty, both readings will
be either low or high.
Repeat above sequence between
grounded heat sink (55) and diode terminals (57 and 58), and then between insulated heat sink (59) and each
diode terminal (56, 57 and 58).
If any set of readings indicates a faulty diode, replace complete rectifier bridge (21).
Test rotor assembly (9) for short of open
Connect multimeter between slip rings
(50), in turn, and rotor shaft (60)
(connection A). Observe resistance
reading on ohmmeter.
Resistance reading should be high
(infinite). If not, rotor (9) is defective and
must be replaced.
Connect multimeter leads across slip
rings (50) (connection B). Observe
resistance reading on ohmmeter. A high
(infinite) resistance reading indicates an
open rotor winding and rotor (9) must be