Alternator: Testing and Inspection

INSPECTION

1. ROTOR




1. Slip ring surface
Inspect slip rings (A) for contamination or any roughness of the sliding surface.
Clean or polish with #500 to #600 emery paper if defective.




2. Slip ring outside diameter
Measure slip ring outside diameter. If slip ring is worn, replace rotor.




3. Continuity test
Check continuity between slip rings (A). If the measured resistance is 1 MOhm or more, replace rotor.




4. Insulation test
Check continuity between slip ring (A) and rotor core (B) or shaft. If the measured resistance is 1 MOhm or less, replace rotor.




5. Ball bearing
Check rear ball bearing. Replace it if it is noisy or if rotor does not turn smoothly.

2. STATOR




1. Continuity test
Inspect stator coil for continuity between its terminals. When there is no continuity (1 MOhm or more) between individual terminals, cable is broken. Replace stator coil.




2. Insulation test
Inspect stator coil for continuity between stator core and each terminal. If there is continuity (1 Ohm or less), replace stator coil.




3. BRUSH
Measure brush length. If brush is worn, replace brush holder assembly.

4. DIODE ASSEMBLY


CAUTION: Never use a high tension insulation tester, such as a meggar as it will damage diodes with its high tension.

The diode consists of eight diodes, four each being located on the positive and negative sides. The diode is necessary to restrict current flow to one direction.




Check all diodes, for continuity. If any diode is faulty, replace diode assembly.




1. Diodes on "+" side
Continuity of proper diodes on "+" side




2. Diodes on "-" side
Continuity of proper diodes on "-" side


5. IC REGULATOR




1. Compose a circuit diagram as shown in figure.




2. Check operation as shown in chart.