3 brush generator question

Rollie NE PA · May 17, 2014

Can I use a 3 brush generator with a 6 volt pos grd regulator? I was told I need to remove the 3rd brush.
Generator passes the motor tests and I have had two new voltage regulators and can not get the system to charge. I tried all of John T's and Bob's instructions.
One thing I was not able to find were wiring instructions for the 3 position light switch, which I am currently bypassing. My field resistor is on the voltage regulator.
When I bought this tractor a couple of years ago it had battery ignition and I switched it to magneto. So I am not currently going thru the light switch.
I hope this makes sense.
Rollie

gene bender · May 17, 2014

Original gen would have had a cut-out with 4 position sw. But you can use a regulator just get the one made for your generator. Check the Delco # on the tag to get the correct one you will also want pos ground cause thats what the rg for that gen will want but you wont need the 4 pos sw your 3 pos sw will work fine with the new reg just wire it withour lead going to the sw just need the lead with batt volts going to the Batt terminal on the reg. The wire you wont use went to a resistor on the 4 pos sw and ws used for hi-charge when a cut-out was used.

Bob Bancroft · May 17, 2014

My experience is with AC. When they went to using a voltage regulator they used two brush generators.

So imagine my surprise when I worked on a neighbors MF 65 and found they had used a three brush generator with a voltage regulator.

I would just adjust the third brush for high output, and the voltage regulator should take care of it. (Assuming you can get it going)

Janicholson · May 17, 2014

I agree with Gene, one 14 gauge wire from Regulator F terminal to the Gen F terminal. One wire from the Reg Bat terminal (10ga) to the amp gauge load side. One wire (10ga) from Arm (or GEN) terminal on the reg to the Arm on the Gen. We assume you polarized the gen by jumping the Bat and Arm terminals on the regulator with a thick wire for one second (tractor not running but everything hooked up). Jim

Rollie NE PA · May 17, 2014

I did polarize the regulator. I hooked up the ammeter and have power on both posts. I know this is dumb, what is the load side of the amp gauge. I wired the gauge to a diagram from a Farmall C manual. I have two other Farmall H's so Maybe I will switch some parts. I might have a new, bad regulator.
Thanks

Owen Aaland · May 17, 2014

The two brush generator and the three brush generator will act the same as far as the regulator is concerned.

The difference in the generator is the two brush generator will have full output voltage applied to the field coils while the three brush unit will have a lower voltage resulting in not being able to provide as many output amps as a similar two brush unit.

Janicholson · May 17, 2014

The Amp gauge has two terminals, one is the the "battery" connected terminal with a #10 wire going to the starter switch and connected to the fat wire going to the battery.
The other terminal is the load side and has lights and the generator output hooked to it. Jim

3 brush generator question

Rollie NE PA

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gene bender

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Bob Bancroft

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Janicholson

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Rollie NE PA

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Owen Aaland

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Janicholson

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