The Ford Barn

Jerry Kzoo · 01-12-2015, 08:50 PM

I have a 3 brush generator that I am struggling to get to charge. I have done the following tests:

It motors in a clockwise direction when a battery charger is put on it. It runs slowly, but not smoothly. Kind of like how the Model A motor turns over - erunh-erunh-erunh

When I put the battery charger on the field coils they draw 4.5 amps

When it is on the engine test stand it will pull in the cutout, but will not show a charge on the ammeter with the engine running at fast idle. I have tested the ammeter with attaching a headlight and it shows discharge and tested another generator with this cutout and it shows charge.

The wire from the generator post to the insulated brush is stiff and somewhat restricts the spring action on that brush, but everything else seems good?? I am stumped.

I appreciate all of your expert guidance and hopefully a solution.

Jerry

RonC · 01-12-2015, 08:58 PM

Did you flash it?

Joe K · 01-12-2015, 09:29 PM

Confirming that it motors in the direction it charges? (i.e. turns in the same direction as the motor drives it)

This would be clockwise as you look at the front (radiator end) of the generator.

https://www.fordbarn.com/forum/showth...rator+rotation

Joe K

Mike V. Florida · 01-13-2015, 01:33 AM

Sounds like a rebuild is in order. While the motoring test will tell you if the unit is bad (no motoring) it will not tell you if it's good, (they can motor and not charge).

Tom Wesenberg · 01-13-2015, 04:15 AM

If that stiff wire to the insulated brush removes some of the brush spring pressure, it will lower the output. I've seen it happen with generators on my test stand. Even the short wire on the ground brush should be positioned in such a way that it doesn't restrict free monement.

So you have power to pull in the cutout but not move the ammeter. I'd check the voltage at the cutout input and output terminals. At fast idle both should be slightly move than idle battery voltage. Both cutout terminals need to be insulated from the case. If this is the style cutout with 2 screws, then the thicker insulator goes on the output side. Make sure neither screw is too long and shorts to the inside of the cutout. The voltage check mentioned should confirm that.

Tom Wesenberg · 01-17-2015, 03:51 PM

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What's up with this generator? Any progress?

01-12-2015, 08:50 PM	#1
Jerry Kzoo Senior Member Join Date: May 2010 Location: Kalamazoo, MI Posts: 173	Puzzling Generator I have a 3 brush generator that I am struggling to get to charge. I have done the following tests: It motors in a clockwise direction when a battery charger is put on it. It runs slowly, but not smoothly. Kind of like how the Model A motor turns over - erunh-erunh-erunh When I put the battery charger on the field coils they draw 4.5 amps When it is on the engine test stand it will pull in the cutout, but will not show a charge on the ammeter with the engine running at fast idle. I have tested the ammeter with attaching a headlight and it shows discharge and tested another generator with this cutout and it shows charge. The wire from the generator post to the insulated brush is stiff and somewhat restricts the spring action on that brush, but everything else seems good?? I am stumped. I appreciate all of your expert guidance and hopefully a solution. Jerry

01-12-2015, 08:58 PM	#2
RonC Senior Member Join Date: May 2010 Location: Rhode Island Posts: 1,868	Re: Puzzling Generator Did you flash it?

01-12-2015, 09:29 PM	#3
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,610	Re: Puzzling Generator Confirming that it motors in the direction it charges? (i.e. turns in the same direction as the motor drives it) This would be clockwise as you look at the front (radiator end) of the generator. https://www.fordbarn.com/forum/showth...rator+rotation Joe K __________________ Shudda kept the horse.

01-13-2015, 01:33 AM	#4
Mike V. Florida Senior Member Join Date: May 2010 Location: Florida between Sarasota and TampaSouth Florida Posts: 14,054	Re: Puzzling Generator Sounds like a rebuild is in order. While the motoring test will tell you if the unit is bad (no motoring) it will not tell you if it's good, (they can motor and not charge). __________________ What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II

01-13-2015, 04:15 AM	#5
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Puzzling Generator If that stiff wire to the insulated brush removes some of the brush spring pressure, it will lower the output. I've seen it happen with generators on my test stand. Even the short wire on the ground brush should be positioned in such a way that it doesn't restrict free monement. So you have power to pull in the cutout but not move the ammeter. I'd check the voltage at the cutout input and output terminals. At fast idle both should be slightly move than idle battery voltage. Both cutout terminals need to be insulated from the case. If this is the style cutout with 2 screws, then the thicker insulator goes on the output side. Make sure neither screw is too long and shorts to the inside of the cutout. The voltage check mentioned should confirm that.

01-17-2015, 03:51 PM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Puzzling Generator Sponsored Links (Register now to hide all advertisements) What's up with this generator? Any progress?