Farmall A generator question

BIGR · Jul 6, 2008

I restored a '46 "A" last year and it just dawned on me in the 4th parade that I never have seen the amp meter move discharge or charge. Never thought of it before. The generator was rebuilt before I put it on by a local shop. Somewhere I remember that you have to do something to the generator when it comes off before it goes back on. Excite or something? Just wondering if I need to do something or maybe the original amp meter that I painted up is bad. Any ideas on what and how to check? Thanks in advance!

55 50 Ron · Jul 6, 2008

The word that needs doing is "polarize". It's done by using a short piece of wire and touching the bare ends from the voltage regulator BAT terminal to the A terminal, Just touch it momentarily, there should be a small spark. Don't hold the wire there after you see the spark. If it doesn't charge after that, try grounding the FLD terminal to the generator case. It should show charge if the generator is good. That would indicate that your voltage regulator is probably bad or as you mentioned your ammeter could be bad. Probably the very first thing to do is to clean ALL your connections, then do the other suggestions.

BIGR · Jul 6, 2008

Voltage regulator was new when the generator was rebuilt. All the connections are new along with new switches and wiring harness. I'll try your idea tomorrow. Thanks!

Red Mist · Jul 6, 2008

You beat me to it, Ron. Good answer. mike

Anonymous-0 · Jul 6, 2008

I would use an ohm meter to check all componets to be sure they are grounded to the frame. Best to put one lead on the ground post of the battery then using the other probe check all connections for ground even the case on the steering post.

Janicholson · Jul 6, 2008

If the needle moves to - when the lights are on and the tractor is not running, The gauge is probably OK.
If it never moves, the gauge could be bad, or the gauge could be connected with some of the wires on the wrong terminal. Check the charging voltage at the battery. When running 1/2 throttle or more. It should be 7.2 to 7.3 volts. JimN

HENRY E NC · Jul 6, 2008

I just finished a year of anguish getting my generator to work properly on my A. Gene Bender is right about the ground. Check to make sure the generator and VR are both grounded well. Are you using 12 Volt coil and distributor or mag and 6 V starting, and lights? Positive or negative ground. If using 6V positive ground with a 6 volt VR make sure the VR is marked for positive ground. After a complete rebuild mine only charged once at 8 volts and over 20 amps and cooked my battery. Took it apart and found two brush wires touching. After insulating them with liquid tape it now runs great. Nuff said Henry

Anonymous-0 · Jul 7, 2008

Mine doesn't have an 'A' terminal. Is that the same as GEN on the opposite side of the other ones (f,l,bat)? Thanks

55 50 Ron · Jul 7, 2008

Yes A for Armature and GEN for generator are used interchangeably.

Farmall A generator question

BIGR

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55 50 Ron

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BIGR

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Red Mist

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Anonymous-0

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Janicholson

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HENRY E NC

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Anonymous-0

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55 50 Ron

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