Generator Inspection

Using a vernier caliper, measure the brush length.

Standard length:

9.5 to 11.5 mm (0.374 to 0.453 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 generator rotor assembly.

Check the generator rotor for an open circuit.

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   Slip ring - Slip ring	20°C (68°F)	1.85 to 2.25 Ω

   Text in Illustration

   *1

   Slip Ring

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

Check if the generator rotor is grounded.

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   Slip ring - Rotor Core	Always	10 kΩ or higher

   Text in Illustration

   *1	Rotor Core
   *2	Slip Ring

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

Check each slip ring.

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





2. Using a vernier caliper, measure the slip ring diameter.
   

   Standard diameter:

   14.2 to 14.8 mm (0.559 to 0.583 in.)
   

   Minimum diameter:

   14.0 mm (0.551 in.)
   

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