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DC 69 11-30-2019 11:45 AM

Generator Brush Adjustment

1 Attachment(s)
Good morning,

From the description in the Les Andrews book, I believe I have a 30/31 generator (photo of end plate w/brushes attached).

Was driving one day and noticed my ammeter was registering 0 amps. I've done most of the work on my '29 CCPU, but I was intimidated by the thought of taking the generator apart to see if there was an obvious reason for the 0 amp reading. I followed the instructions in the book and my fears were gone (not as complicated as I thought).

The problem was one of the brush screws came out and the wire was disconnected. I easily re-connected the brush & wire and started it right up, but now the ammeter is reading 20 amps wth RPMS increased (all lights off).

Question: Which is the 3rd brush? Is it adjustable? If so, how?

Any help is greatly appreciated. Thanks

redmodelt 11-30-2019 11:56 AM

Re: Generator Brush Adjustment

1 Attachment(s)
It's the one on the slip ring, you should be able to move it without loosing anything;

Purdy Swoft 11-30-2019 03:54 PM

Re: Generator Brush Adjustment

push downward on the adjustable brush that is pictured , to increase the charge rate . The slip ring should slightly rotate when pushed down or raised up .

DC 69 11-30-2019 04:42 PM

Re: Generator Brush Adjustment

Thanks for the help redmodelt & Purdy Swoft.

I was cleaning it up and was able to determine the 3rd brush arm is connected to the slip ring. The other thing I noticed was the 3rd brush arm is copper colored while the others are silver. I'm waiting for new brushes, then re-installing.

I'm also guessing the closer the 3rd brush is to the other = higher amp output. (?)

Purdy Swoft 11-30-2019 05:09 PM

Re: Generator Brush Adjustment

Yes , The slip ring will rotate only so far . If a voltage regulator is used it will allow the generator to cycle between higher and lower charge rate to prevent overcharging the battery . When a voltage regulator isn't used , the adjustable brush needs to be set for a lower charge rate because the generator will charge the same rate most of the time without cycling .

I use the Fun Projects voltage regulator that takes the place of the cutout . I set the third brush for a ten amp maximum charge . In normal operation the generator would only charge a short time on ten amps . Ten amps would quickly charge the battery . Higher amps will only be needed when the lights are used . The ammeter will mostly show a discharge when the lights are on . It takes a good while to kill the battery so not to worry too much .

Tom Wesenberg 12-02-2019 01:29 PM

Re: Generator Brush Adjustment

The ground brush is the one with the short bare ground wire, and the closer you move the adjustable brush to the ground brush, the more you LOWER the output. For normal driving, about 2 to 3 amps should be plenty. When using the headlamps, you want to move the adjustable brush down towards the output brush, so you have more amps to power the lights.

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