tractor gen

[danl]

Any generator experts here?

I have Massey 135 with 12 volt gen. that quit.
The brushes are pretty bad but not gone. I cleaned the commuter on the armature and sanded it off. When I turn it with impact wrench it puts out .6 volts.

What puzzles me is that I have continuity through the field and not to the case, when the armature is out of the gen. When I replace the armature I show continuity from both the A post and the Field post back to the case.

Does this mean my armature is shorted?
I would put a alternator on it but I will lose my tachometer as it runs on a gear on the generator shaft.

Thanks

[lavacarancher]

Dan, there should be no resistance from the armature to ground. Even the field should not read to ground when it is not connected to the regulator on most generator/regulator systems.

Sometimes the field will lose residual magnetics and will need to be "flashed" from time-to-time. Flashing the field involves attaching a wire to the battery positive terminal and raking the other end of the wire quickly across the field connection. DO NOT camp out on the field terminal as it will burn the field windings up.