Field Open or Short Circuit Test

Alternator W/Integral Regulator Field Open Or Short Circuit Test:

This test is performed with an ohmmeter, Rotunda Dwell-Tach-Volt-Ohmmeter 059-00010 or equivalent. Place the Multiply-By setting at 1 and calibrate the ohmmeter.

NOTE: Text values shown in brackets [ ]___ are referenced to Rotunda Model 059-00010 and may be different if another tester is used.

1. Contact the regulator A blade terminal with one probe and the regulator F screw head with the other probe. Spin the alternator pulley. Reverse the ohmmeter probes and repeat the test. In one probe direction, the ohmmeter reading should be between 2.2 and 100 ohms (on Rotunda meter) and may fluctuate while the pulley is turning. In the other probe direction, the reading should fluctuate between 2.2 and about [9]___ohms.
2. An infinite reading (no meter movement) in one direction and approximately [9]___ohms in the other, indicates an open brush lead, worn or stuck brushes, a damaged rotor or a loose regulator to brush holder attaching screw.
3. An ohmmeter reading less than [2.2]___ohms in both directions indicates a shorted rotor or damaged regulator.
4. An ohmmeter reading significantly over [9]___ohms in both directions indicates an inoperative regulator or loose F terminal screw.
5. Contact the alternator rear housing with one ohmmeter probe and touch the other probe to the regulator F terminal. REVERSE the probes and repeat the test. The ohmmeter reading should be infinite in one probe direction and approximately [9]___ohms in the other. A reading less than infinite in both directions indicates a grounded brush lead or an inoperative regulator. A reading significantly over [9]___ohms in both directions indicates an inoperative regulator or a damaged A terminal connection.