Alternator: Testing and Inspection

3MZ-FE CHARGING: GENERATOR:

INSPECTION

1. INSPECT GENERATOR BRUSH HOLDER ASSEMBLY





(a) Check the brush length.
(1) Using a vernier caliper, measure the exposed brush length.
Specified brush length:
4.5 to10.5 mm (0.177 to 0.413 in.)
If the exposed brush length is less than the minimum, replace the brush holder assembly.
2. INSPECT GENERATOR ROTOR ASSEMBLY





(a) Check that the bearing is not rough or worn.
If necessary, replace the rotor assembly.





(b) Check if the rotor has an open circuit.
(1) Measure the resistance between the slip ring.
Resistance:
2.3 to 2.7 Ohms at 20°C (68°F)
If the result is not as specified, replace the rotor assembly.





(c) Check if the rotor is grounded.
(1) Measure the resistance between the slip ring and the rotor core.
Resistance:
10 kOhms or higher
If the result is not as specified, 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 rotor assembly.





(e) Check the slip ring diameter.
(1) Using a vernier caliper, measure the slip ring diameter.
Specified diameter:
14.0 to 14.4 mm (0.551 to 0.567 in.)
If the diameter is less than minimum, replace the rotor assembly.
3. INSPECT GENERATOR DRIVE END FRAME BEARING





(a) Check that the bearing is not rough or worn.
If necessary, replace the bearing.