Generator Inspection

Using a vernier caliper, measure the brush length.

Standard length:

10.5 mm (0.417 in.)

Minimum length:

4.5 mm (0.177 in.)

Check that the bearing is not rough or worn and that it rotates smoothly.
If necessary, replace the rotor assembly.

Check the resistance.

1. Measure the resistance between the slip rings.
   

   Standard resistance:

   1.85 to 2.25 Ω at 20°C (68°F)
   

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




2. Measure the resistance between the slip ring and rotor core.
   

   Standard resistance:

   10 kΩ or higher
   

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

Check each slip ring.

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





2. 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.