SCJ and 8SC Series Alternators Caterpillar

Field Winding Continuity Test

Illustration 1	g01065374
Rotor Assembly (3) Slip Rings (4) Rotor (5) Rotor Shaft

1. Set the multimeter to the 200 ohm resistance scale. Measure the resistance between the slip rings (3) .

2. The resistance between the slip rings (3) should be within the following values.

   Resistance of field winding at 24 °C (75 °F)

   184-7171 Alternator Gp ... 5.29 to 5.69 Ohms

   220-4995 Alternator Gp ... 5.29 to 5.69 Ohms

   150-1935 Alternator Gp ... 6.52 to 6.88 Ohms

   215-5568 Alternator Gp ... 6.52 to 6.88 Ohms

   264-0511 Alternator Gp ... 3.19 to 3.74 Ohms

3. Replace the rotor (4) if the measurement is incorrect.

Field Winding Ground Test

1. Set the multimeter to the 20 M ohm resistance scale. Measure the resistance between one of the slip rings (3) and the rotor shaft (5) .

2. The multimeter reading should be greater than 100 K Ohms (0.100 M Ohms).

3. Replace the rotor (4) if the multimeter reading is low. Low resistance indicates undesired continuity between the field winding and the rotor shaft.

4. Repeat steps 1 through 3 for the other slip ring (3) .