Alternator: Testing and Inspection

INSPECTION




1. INSPECT GENERATOR BRUSH HOLDER ASSEMBLY
a. 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 brush holder.




2. INSPECT GENERATOR ROTOR ASSEMBLY
a. Check the rotor open circuit.
1. Using an ohmmeter, measure the resistance between the slip rings.

Resistance: 2.3 to 2.7 ohms at 20 °C (68 °F)

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




b. Check the rotor ground.
1. Using an ohmmeter, check that there is no continuity between the slip ring and rotor.

If there is continuity, replace the rotor.

c. Inspect slip rings.
1. Check that the slip rings are not rough or scored.

If rough or scored, replace the rotor.




2. Using vernier calipers, measure the slip ring diameter.

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

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




3. INSPECT GENERATOR ROTOR BEARING
a. Check the bearing is not rough or worn.

If necessary, replace the bearing.




4. REMOVE GENERATOR ROTOR BEARING
a. Using SST, remove the bearing cover (outside) and bearing.

SST 09820-00021

NOTE: Be careful not to damage the fan.

b. Remove the bearing cover (Inside).




5. INSTALL GENERATOR ROTOR BEARING
a. Place the rotor on the pulley.
b. Install the bearing cover (Inside).
c. Using SST and a press, press in a new bearing.

SST 09820-00031




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

SST 09285-76010




6. INSPECT GENERATOR DRIVE END FRAME BEARING
a. Check the bearing is not rough or worn.

If necessary, replace the bearing.




7. REMOVE GENERATOR DRIVE END FRAME BEARING
a. Remove the 4 screws and retainer plate.




b. Using SST, tap out the bearing.

SST 09950-60010 (09951-00250), 09950-70010 (09951-07100)




8. INSTALL GENERATOR DRIVE END FRAME BEARING
a. Using SST and a press, press in a new bearing.

SST 09950-60010 (09951-00470), 09950-70010 (09951-07100)

b. Install the retainer plate with the 4 screws.

Torque: 2.6 N.m (27 kgf.cm, 23 in.lbf)