Inspection

60 A / 70 A Types

Rotor




- Using ohmmeter, check for continuity between slip rings of rotor. If there is no continuity, replace rotor (1).

Resistance between slip rings of rotor (for 60 / 70 A types) 2.5 - 2.9 Ohm




- Using ohmmeter, check that there is no continuity between slip ring and rotor core. If there is continuity, replace rotor (1).
- Check slip rings for roughness or scoring. If rough or scored, replace rotor.

Stator




- Using ohmmeter, check all leads for continuity. If there is no continuity, replace stator (1).




- Using ohmmeter, check that there is no continuity between coil leads (2) and stator core (1). If there is continuity, replace stator.

Brush and brush holder




Check each brush for wear by measuring its length. If brush is found worn down to service limit, replace brush.

Brush length "a" (for 60 / 70 A types)
Standard: 16 mm (0.63 in.)
Limit: 2 mm (0.08 in.)

Rectifier
1. Using ohmmeter, check continuity between each of upper and lower rectifier bodies and each diode lead (2). Check both directions by reversing probes of ohmmeter and there should be only one-way continuity in each case. If check result is not satisfactory, replace rectifier (1).




2. In the same manner as described in above Step 1), check that there is only one-way continuity between both leads of diode trio.

Condenser




Check condenser capacity.

Condenser capacity: 0.5 micro F

80 A Type

Rotor




- Using ohmmeter, check for continuity between slip rings of rotor. If there is no continuity, replace rotor.

Resistance between slip rings of rotor (for 80 A type): About 2.9 Ohm




- Using ohmmeter, check that there is no continuity between slip ring and rotor. If there is continuity, replace rotor.




- Check slip rings for roughness or scoring. If rough or scored, replace rotor.
Using a vernier caliper, measure the slip ring diameter. If the diameter is less than minimum, replace the rotor.

Standard diameter of slip ring: 14.2 - 14.4 mm (0.559 - 0.567 in.)

Minimum diameter of slip ring: 12.8 mm (0.504 in.)

Stator




- Using ohmmeter, check all leads for continuity. If there is no continuity, replace stator.




- Using ohmmeter, check that there is no continuity between coil leads and stator core. If there is continuity, replace stator.

Brush and brush holder




Check each brush for wear by measuring its length as shown. If brush is found worn down to service limit, replace brush.

Exposed brush length "a" (for 80 A type)
Standard: 10.5 mm (0.413 in.)
Limit: 4.5 mm (0.177 in.)

Rectifier




- Positive rectifier
a. Using an ohmmeter, connect one tester probe to the "B" terminal (1) and the other to each rectifier terminal (2).
b. Reverse the polarity of the tester probes and repeat Step 1).
c. Check that one shows continuity and the other shows no continuity. If there is continuity, replace the rectifier.




- Negative Rectifier
a. Using an ohmmeter, connect one tester probe to each negative terminal (1) and the other to each rectifier terminal (2).
b. Reverse the polarity of the tester probes and repeat Step 1).
c. Check that one shows continuity and the other shows no continuity. If there is continuity, replace the rectifier.

Bearing




- Check that drive and bearing is not rough or worn.




- Check that end housing bearing is not rough or worn.