Alternator: Testing and Inspection

GENERATOR

INSPECTION

1. INSPECT GENERATOR BRUSH HOLDER ASSEMBLY




a. Check the brush length. (100 A Generator)
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.




b. Check the brush length. (130 A Generator)
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 that bearing is not rough or worn.

If necessary, replace the generator rotor. (100 A Generator)
If necessary, replace the generator rotor bearing. (130 A Generator)




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

Resistance:
2.3 to 2.7 Ohms at 20 degrees (68 degrees) for 100 A Generator
1.5 to 1.9 Ohms at 20 degrees (68 degrees) for 130 A Generator

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




c. Check if the rotor has ground.
1. Using an ohmmeter, check that there is no continuity between the slip ring and 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. REMOVE GENERATOR ROTOR BEARING
a. 130 A generator
1. Using SST, remove the generator bearing cover (outside) and bearing. SST 09820-00021

NOTE: Be careful not to damage the fan.

2. Remove the generator bearing cover (inside).

4. INSTALL GENERATOR ROTOR BEARING
a. 130 A generator




1. Place the generator rotor on the generator pulley
2. Install the generator bearing cover (inside).
3. Using SST and a press, press in a new bearing.

SST 09820-00031




4. Using SST, push in the generator bearing cover (outside).

SST 09285-76010




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