Generator question

[Paul from Maine]

Generator quit working so removed it to the bench. All brushes worn down so that the brush holders were rubbing on the armature. No new brushes available on Saturday, so elongated the brush holes, shimmed the top of the brushes with tape, reinstalled generator and it now charges fine. For fun I connected a voltmeter to generator post on generator side of the cut out. At idle it read seven volts. wheneverer I reved up the motor the voltmeter would read zero. Slow down to idle and voltmeter would jump back up to seven volts. Repeated it several times. Clamped voltmeter lead under generator post nut to ensure good connection and bolted other lead to clean ground. Repeated several times again and same result. Drove a hundred miles Sunday and generator was charging strong. Why the voltage drop to zero at speeds above idle? I can't figure it out!

[Tom Wesenberg]

Do you have a picture of the generator? The model A generator brushes should have slots, not holes, so there is no need to elongate them to slide them out for a bit more use. Also the Model A brush holders should have stops to prevent them from contacting the commutator when the brush is worn out.

Did you use an analog meter, or a digital meter?

[Paul from Maine]

Originally Posted by Tom Wesenberg

Do you have a picture of the generator? The model A generator brushes should have slots, not holes, so there is no need to elongate them to slide them out for a bit more use. Also the Model A brush holders should have stops to prevent them from contacting the commutator when the brush is worn out.

Did you use an analog meter, or a digital meter?

I was using an old Holt voltmeter which I have used in the past to monitor the electrical system voltage at the starter. My car dates from 1929 and has the original motor. Car had been sitting in a barn since the 1950's before I got it. I had the motor rebuilt 2 years ago, but rebuilder had me remove and keep the generator, so he never touched it. Brushes must be atleast fifty years old and did not have slots like in the othe r generator I have. I am running somekind of evr I bought from Macs a couple of years ago, but the meter is connected forward of the regulator right at the generator post. Amp meter shows a 1 or 2 amp charge once it settles back from cranking. When gennie wasn't charging, amp meter showed a one amp discharge.

[Tom Wesenberg]

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Do you have some pictures of the brushes and commutator?

Also a picture of the regulator?