M20C-FKS BATTERY / CHARGING  GENERATOR  INSPECTION  

0.698,0.688 0.875,0.854 0.177,0.167 10 *a

*a

Length

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

Standard exposed brush length:

9.5 to 11.5 mm (0.374 to 0.453 in.)

Minimum exposed brush length:

4.5 mm (0.177 in.)

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

Check the generator rotor assembly for an open circuit.

i.

1.698,0.896 2.406,0.417 2.406,0.417 1.854,0.948 true 2.469,0.281 2.781,0.438 0.313,0.156 10 false *a

*a

Slip Ring

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)	1.6 to 2.0 Ω

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

Check the generator rotor assembly for a short to ground.

i.

0.333,0.188 0.646,0.188 0.646,0.188 0.948,0.781 true 1.802,1 2.135,0.615 2.135,0.615 2.396,0.615 true 2.438,0.531 2.75,0.688 0.313,0.156 10 false *a 0.167,0.083 0.479,0.24 0.313,0.156 10 false *b

*a	Slip Ring
*b	Rotor

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Slip ring - Rotor	Always	1 MΩ or higher

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

Check that the generator rotor bearing is not rough or worn and that it rotates smoothly.

If the generator rotor bearing is rough or worn, or does not rotate smoothly, replace the generator rotor assembly.

Check the slip ring.

ii.

0.552,0.596 0.712,0.748 0.16,0.152 10 *a

*a

Diameter

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.

Check that the generator drive end frame bearing is not rough or worn and that it rotates smoothly.

If the generator drive end frame bearing is rough or worn, or does not rotate smoothly, replace the generator drive end frame bearing.