The Ford Barn

jhowes · 11-01-2017, 03:22 PM

This question is about a non Model A generator. I have an unknown (to me) generator that has two wires coming out of the case. One is marked F and the other is A. As I understand it the F (field) can be grounded for testing and the A (armature) terminal goes through an amp meter to the battery. The inside of this generator looks good with what appears to be new brushes but I am concerned with hooking it up to my test rig because I don't know if it is a positive or negative ground system that the generator came from. Is there a way to tell and how do you polarize a generator with two wires coming out of it? I know there are some knowledgeable guys on this forum that can guide me in the right direction. Thanks, Jack

Mike V. Florida · 11-01-2017, 03:58 PM

Polarize by taking the A wire and connecting it to polarity you want on the battery while the F is connected to the case. It should spin if good.

jhowes · 11-01-2017, 04:09 PM

Mike, if I understand you correctly it doesn't matter what the generator came out of (+ or -) ground, it will work either way as long as I ground the field and put power to the armature connection. Thanks for the lesson in generators. Jack

Tom Wesenberg · 11-01-2017, 07:48 PM

Does it have an adjustable third brush?

jhowes · 11-01-2017, 09:03 PM

Tom; It has a third brush but I don't know if it is adjustable yet. I'll check tomorrow. Jack

Tom Wesenberg · 11-01-2017, 09:13 PM

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Most likely it is, so just do what Mike said.
In fact is you don't have a voltage regulator, then the field wire is permanently grounded, and the output is adjusted by the third brush.

11-01-2017, 03:22 PM	#1
jhowes Senior Member Join Date: Jul 2010 Location: upstate NY near Mass border Posts: 789	generaator This question is about a non Model A generator. I have an unknown (to me) generator that has two wires coming out of the case. One is marked F and the other is A. As I understand it the F (field) can be grounded for testing and the A (armature) terminal goes through an amp meter to the battery. The inside of this generator looks good with what appears to be new brushes but I am concerned with hooking it up to my test rig because I don't know if it is a positive or negative ground system that the generator came from. Is there a way to tell and how do you polarize a generator with two wires coming out of it? I know there are some knowledgeable guys on this forum that can guide me in the right direction. Thanks, Jack

11-01-2017, 03:58 PM	#2
Mike V. Florida Senior Member Join Date: May 2010 Location: South Florida Posts: 14,054	Re: generaator Polarize by taking the A wire and connecting it to polarity you want on the battery while the F is connected to the case. It should spin if good. __________________ 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

11-01-2017, 04:09 PM	#3
jhowes Senior Member Join Date: Jul 2010 Location: upstate NY near Mass border Posts: 789	Re: generaator Mike, if I understand you correctly it doesn't matter what the generator came out of (+ or -) ground, it will work either way as long as I ground the field and put power to the armature connection. Thanks for the lesson in generators. Jack

11-01-2017, 07:48 PM	#4
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: generaator Does it have an adjustable third brush?

11-01-2017, 09:03 PM	#5
jhowes Senior Member Join Date: Jul 2010 Location: upstate NY near Mass border Posts: 789	Re: generaator Tom; It has a third brush but I don't know if it is adjustable yet. I'll check tomorrow. Jack

11-01-2017, 09:13 PM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: generaator Sponsored Links (Register now to hide all advertisements) Most likely it is, so just do what Mike said. In fact is you don't have a voltage regulator, then the field wire is permanently grounded, and the output is adjusted by the third brush.