What is the residual voltage output at the armature terminal of the generator? With all wires disconnected, a polarized generator should produce at least 1/2 volt DC. If you ground the Field terminal the voltage at the armature terminal should rise, and go very high if the RPM is increased. A generator that passes those two tests will charge the battery. Move on to checking wire continuity and regulator functions. It is difficult to damage a DC generator short of burning up wires with a dead short.

A good analog (not digital) voltmeter and ammeter are pretty essential to getting a good diagnosis of a generator-type charging system. Digital meters are just too sensitive and quick-responding to get good information from a vibrating-contact regulator.
Jerry

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