Alternator: Testing and Inspection

ALTERNATOR NOT CHARGING

1. Drive belt slipping.
2. Open in charging or ground circuits.
3. Defective brushes, regulator or diodes.
4. Broken excitation circuit or rotor winding.
5. Open stator ground circuit.

INSUFFICIENT OR IRREGULAR POWER SUPPLY

1. Drive belt slipping.
2. Defective brushes, regulator, or diode rectifiers.
3. Partial short circuit in rotor.
4. Poor stator to ground connection.

CURRENT TOO HIGH

1. Defective regulator.
2. Poor contact between regulator and alternator.

NOISY ALTERNATOR

1. Worn drive belt.
2. Pulley fitted incorrectly.
3. Loose alternator brackets.
4. Alternator and crankshaft pulleys misaligned.
5. Worn or defective bearings.
6. Short circuit in diode rectifier.