Generator issues

[MBI Houston]

Hi Folks:

Installed a rebuilt generator and new cutoff switch with diodes. When I try to set the third brush I can only get either a +20 or higher or 0 reading on the ammeter. If I turn on the headlights the reading goes to +8 add the horn and it goes to +4 when it is set to +20. When set at 0 it goes negative. I also did the hot wire to make sure the polarity was correct.

Any ideas?

Thanks,
Marshall

[Tom Wesenberg]

So no one is confused I know you meant "CUTOUT" when you said "cutoff switch", and you have a diode type cutout. Are you moving the adjustable brush in very small increments? I know they can be tricky and you may be moving the brush from one extreme to the other. I like to use an insulated screwdriver and use the generator case opening as a pivot point, so you can get some nice leverage to make small adjustments.

Personally I never use an adjustable brush but use my EVR, which fits in place of the adjustable brush and it's holder.

If you are able to make small brush adjustments, but the amp guage still only shows 0 or 20 amps, I'd check for a poor connection somewhere in the charging circuit.

[Ron in Quincy]

It is possible the movable brush is wired to the output instead of to the field ? When the insulated brushes are reversed wired you get full charge and no control of charge rate.

Ron

[Tom Wesenberg]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by Ron in Quincy

It is possible the movable brush is wired to the output instead of to the field ? When the insulated brushes are reversed wired you get full charge and no control of charge rate.

Ron

Ron brings up a very good point. I've worked on 2 generators in the past couple years that were rebuilt by generator shops. Both had the field and output wires connected to the wrong brushes, and both generators were toast. If your generator isn't cooked yet, you might want to take it apart and check it out. The output wire on the generators with a rear ball bearing are taped to the side of the field coil, so the output and field wires are more easily mixed up than on the later generator with a rear bushing and the output post at the rear of the case.