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How to Test Delco Generators

Liz Tomas

Delco originally built automotive engines and generators but their products are used in many other applications. By testing the generator, it is possible to determine where the generator problems are coming from. With a generator, the voltage should increase when the generator is running. If this is not the case then you need to uncover where the generator is not functioning properly. A multimeter can help narrow down where the problems occur.

  1. Remove the field wires and the armature wires from the generator. Cover the ends of the wires with electrical tape to prevent damage.

  2. Attach a jumper cable from the generator field post to an airframe ground.

  3. Attach a DC voltmeter to the armature terminal of the generator. The plus side of the meter connects to the field post and the negative side connects to the ground.

  4. Watch the voltage as the throttle increases. The faster the generator field, the more energy output. If the voltage does not increase, then you need to check if the engine needs to be polarized. Your generator may also be faulty.