Alternator - Bosch K1/N1 Caterpillar

Rotor Field Winding Continuity - Test

Illustration 1	g03222017
Rotor field winding continuity test (1) Rotor (2) Slip ring

1. Put the multimeter on the 200 ohm resistance (Ohms) scale. Touch the meter leads to each slip ring (2) on rotor (1) as shown in Illustration 1.

2. The resistance values should be as follows. See specifications for the K1, 24 V alternators.

   3E-7295 Charging Alternator Gp, and 9X-0341 Charging Alternator Gp ... 2.47 to 2.75 ohms

   8C-5535 Charging Alternator Gp, and 7T-2876 Charging Alternator Gp ... 3.4 to 3.7 ohms

   9W-3043 Charging Alternator Gp ... 9.0 to 9.9 ohms

   2Y-4212 Charging Alternator Gp ... 18 to 22 ohms

   2Y-8310 Charging Alternator Gp ... 14.4 to 17.6 ohms

3. If the resistance is not correct, the rotor is open or shorted and must be replaced.

Rotor Field Winding Ground - Test

Illustration 2	g03222043
Rotor field winding continuity test (1) Rotor (2) Slip ring

1. Put the multimeter on the 20M resistance (Ohms) scale. Touch the meter leads between each slip ring (2) and the rotor shaft.

2. Both readings should be 100000 ohms or greater (meter reading 0.10 or greater).

3. If the meter reading is low, the rotor is grounded and must be replaced.