Inspection

INSPECTION




1. INSPECT GENERATOR BRUSH HOLDER ASSEMBLY
a. Check the brush length.
1. Using vernier calipers, measure the exposed brush length.

Standard exposed brush length: 10.5 mm (0.413 in.)
Minimum exposed brush length: 4.5 mm (0.177 in.)

If the exposed brush length is less than minimum, replace the generator brush holder.

2. INSPECT GENERATOR ROTOR ASSEMBLY




a. Check the bearing is not rough or worn.
If necessary, replace the generator rotor.




b. Check the rotor for open circuit.
1. Using an ohmmeter, measure the resistance between the slip ring.

Resistance:
2.3 to 2.7 Ohms at 20 degrees C (68 degrees F) for 130A
1.5 to 1.9 Ohms at 20 degrees C (68 degrees F) for 150A

If the resistance is not as specified, replace the generator rotor.




c. Check the rotor for ground.
1. Using an ohmmeter, check that there is no continuity between the slip ring and the rotor core.
If there is continuity, replace the generator rotor.

d. Inspect slip rings.
1. Check that the slip rings are not rough or scored.
If rough or scored, replace the generator rotor.




e. Check the slip ring diameter.
1. Using vernier calipers, measure the slip ring diameter.

Standard diameter: 14.2 to 14.4 mm (0.559 to 0.567 in.)
Minimum diameter: 14.0 mm (0.551 in.)

If the diameter is less than minimum, replace the generator rotor.




3. INSPECT GENERATOR DRIVE END FRAME BEARING
a. Check the bearing is not rough or worn.
If necessary, replace the bearing.