Rectifier Diode / Bridge: Testing and Inspection

AR15.40-P-9301-02R Test Diodes For Alternator
- ENGINE 113.### 1#, 112.275 in MODEL 230.### 1#
- ENGINE 155 in MODEL 199








shown on model 230

Connection diagram

030 Engine tester with oscilloscope
065 Current measurement pliers

G1 On-board electrical system battery
G1/4 Starter battery
G2 Alternator
N82/1 Vehicle power supply control unit





1 Connect engine tester with oscilloscope to alternator (G2)

Connect current clamp (65) to positive lead (3) from bottom at alternator (G2).

2 Start engine.
3 Switch on low beam.

It is not possible in this test to assess the exciter diodes.

4 Assess diode harmonics at 3000 rpm (engine speed).





Harmonics, if diodes are OK (peak stresses possible but of no significance) (example).





Harmonics, if a positive diode is faulty (example).





Harmonics, if a negative diode is defective (example).





Short circuit of a positive diode (example)





Short circuit of a negative diode (example)





Ground connection of a winding (example)





Open circuit of a winding (example)