GENERATOR INSPECTION

PROCEDURE

1. INSPECT GENERATOR BRUSH HOLDER ASSEMBLY

   
   
   1. 

      Text in Illustration

      *a

      Length

      Using a vernier caliper, measure the length of the exposed brushes.

      Standard exposed length
      9.5 to 11.5 mm (0.374 to 0.453 in.)

      Minimum exposed length
      4.5 mm (0.177 in.)

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

2. INSPECT GENERATOR ROTOR ASSEMBLY

   
   

   1. 

      Text in Illustration

      *1	Slip Ring
      *2	Ohmmeter

      Check the generator rotor for an open circuit.

      
      

      1. Using an ohmmeter, measure the resistance between the slip rings.

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

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

   2. 

      Text in Illustration

      *1	Slip Ring
      *2	Rotor
      *3	Ohmmeter

      Check the rotor for a short to ground.

      
      

      1. Using an ohmmeter, measure the resistance between one of the slip rings and the rotor.

         Standard Resistance
         Tester Connection Condition Specified Condition Slip ring - Rotor Always 10 MΩ or higher

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

   3. 

      Check that the generator rotor bearing is not rough or worn.

      If necessary, replace the generator rotor bearing.

   4. 

      Text in Illustration

      *a

      Diameter

      Using a vernier caliper, measure the slip ring diameter.

      Standard diameter
      14.2 to 14.8 mm (0.559 to 0.582 in.)

      Minimum diameter
      14.0 mm (0.551 in.)

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

3. INSPECT GENERATOR DRIVE END FRAME BEARING

   
   

   1. 

      Check that the bearing is not rough or worn.

      If necessary, replace the generator drive end frame bearing.