HDB Series and M1 Series Heavy Duty Brushless Alternators Caterpillar

Stator Winding Continuity Test

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Illustration 1	g00825551
Stator Winding Continuity Test (8) Stator (9) Stator leads

1. Remove the rear cover.

2. Disconnect all stator leads (9) from the rectifier.

3. Connect the multimeter leads across any pair of stator leads (9) .

4. Measure the resistance between the stator leads.

   Expected Results:

   6N-9294 Alternator Gp ... 0.2420 ± 0.0180 ohms

   5S-9088 Alternator Gp ... 0.1110 ± 0.0090 ohms OR 0.2220 ± 0.0180 ohms

   100-5047 Alternator Gp ... 0.1110 ± 0.0090 ohms OR 0.2220 ± 0.0180 ohms

   169-3345 Alternator Gp ... 0.1080 ± 0.0060 ohms OR 0.2160 ± 0.0120 ohms

   185-5294 Alternator Gp ... 0.0629 ± 0.0032 ohms OR 0.01258 ± 0.0064 ohms

   177-9953 Alternator Gp ... 0.0381 ± 0.0020 ohms OR 0.0762 ± 0.0040

   197-8820 Alternator Gp ... 0.0267 ± 0.0014 ohms OR 0.0334 ± 0.0028 ohms

   Results:

   OK - The resistance is within tolerance. Repeat steps 1 through 4 for all other possible pairs of stator leads (9). If all of the results are OK, the stator is normal. STOP.

   NOT OK - The resistance is above tolerance. Stator (8) has an open circuit. Replace the stator. STOP.

   NOT OK - The resistance is below tolerance. Stator (8) has a short circuit. Replace the stator. STOP.

Illustration 2	g00824809
The 35 amp alternator has three stator leads: (A), (B) and (C). Measure the resistance three times: (AB), (AC) and (BC) .

Illustration 3	g00824931
The alternators that are greater than 35 amps have four stator leads: (A), (B), (C) and (D). Measure the resistance six times: (AB), (AC), (AD), (BC), (BD) and (CD) .

Stator Winding Ground Test

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Illustration 4	g00825552
Stator Winding Ground Test (7) Rear frame (8) Stator (9) Stator leads

1. The rear cover remains removed from the alternator.

2. Connect the multimeter leads across rear frame (7) and one stator lead (9) .

3. Measure the resistance.

   Expected Result: The resistance is greater than 100000 ohms.

   Results:

   OK - The resistance is greater than 100000 ohms. Repeat steps 1 to 3 for the other stator leads (9). If all of the results are OK, the stator is normal. STOP.

   NOT OK - The resistance is NOT greater than 100000 ohms. Stator (8) is shorted to the frame. Replace the stator. STOP.