Alternator: Testing and Inspection

3UR-FE BATTERY / CHARGING: GENERATOR: INSPECTION

1. INSPECT GENERATOR DRIVE END FRAME BEARING

(a) Rotate the bearing and check that there is no abnormal noise and that it rotates smoothly.





If necessary, replace the bearing Disassembly.

2. INSPECT GENERATOR ROTOR ASSEMBLY

(a) Check the rotor for an open circuit.





(1) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





If the result is not as specified, replace the rotor assembly.

(b) Check if the rotor is grounded.





(1) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





If the result is not as specified, replace the rotor assembly.

(c) Check that the slip rings are not rough or scored.

If rough or scored, replace the rotor assembly.

(d) Using a vernier caliper, 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 the minimum, replace the rotor assembly.

3. INSPECT GENERATOR ROTOR BEARING

(a) Rotate the bearing and check that there is no abnormal noise and that it rotates smoothly.





If necessary, replace the generator rotor.

4. INSPECT GENERATOR BRUSH HOLDER ASSEMBLY





(a) Using a vernier caliper, measure the exposed brush length.

Standard exposed length:

10.5 mm (0.413 in.)

Minimum exposed length:

4.5 mm (0.177 in.)

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