generator on farmall A

Anonymous-0 · Feb 11, 2010

why is the field terminal on my A grounded to the generator casing, somone ran a wire from the terminal to the screw holding the regulator in place.

Bob · Feb 11, 2010

That would "full-field" the generator, making it charge at it's maximum rate.

Perhaps the wiring to the lightswitch was bad or the switch/resistor bad, or the PO was simply a "blem".

gene bender · Feb 11, 2010

Thats been done for many yrs to make them charge more. If you think the rate is too high move the third brush and it will lower the rate. If you are still using the mag you only need a charge rate of a couple amps. You mite want to use an OHM meter to see if all the componets in the charge system have a good ground even the control box on the steering post all need ground for the system to work.

John T · Feb 11, 2010

I can only venture a guess but perhaps the light switch lost its frame ground or the field current control resistor on the switch went bad/open or the wire was bad from the gennys FLD post up to the switch. Any of those can cause the gennys to NOT charge as the FLD post requires either a dead ground for HIGH charge or a resistive ground for LOW charge. If the FLD post is permanently dead frame grounded the battery could become overcharged BUTTTTTTTTTT that depends on the RPM and the battery and how long its ran at fast RPM and the shape of the genny and its 3rd brush location if so equipped, and if its a Magneto or coil ignition, depending on many things it may not get overcharged either.

John T

Nebraska Cowman · Feb 11, 2010

Yep, pretty common "fix" for slow charging gennys. I have a couple that way myself. If I think the battery is over charging I pull the wire off for a while.

Bill Shaver · Feb 11, 2010

Yes i see that, it charges fully like this, looked inside and seeing the brushes have not much to go, my reason for the question concerns my other tractor, a massey harris 30, noted the resistor burnt, and changed out the relay for a 2 coil voltage regulator. tractor charges up, but when you shut it off it ammmter goes into discharge. The farmall A does not have this problem the resistor is still in the switch box, all functional, lights & box has a ground as well, but its generator has a 2 coil regulator, not a relay, tractor has a distributor not a mag. trying to figure out this problem on my MH 30.

John T · Feb 11, 2010

My Troubleshooting Procedure covers non charging problems for BOTH Voltage Regulator OR Cutout Relay systems......Give it a try, it may help.

John T
John Ts Troubleshooting Procedure

Bill Shaver · Feb 11, 2010

okay I'll give it a read, thank you Bill Shaver

Jim Becker · Feb 12, 2010

(quoted from post at 12:05:37 02/11/10) but when you shut it off it ammmter goes into discharge.

First thing, unhook your battery and see where "zero" really is on your ammeter. A lot of the needles aren't very well centered.

Bill Shaver · Feb 12, 2010

Yes verified needle is in center of ammeter, took a chance & hooked up the field conn from the resistor switch & it some how cured the problem, when machine is shut off needle now returns to center.

generator on farmall A

Anonymous-0

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Bob

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gene bender

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John T

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Nebraska Cowman

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Bill Shaver

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John T

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Bill Shaver

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Jim Becker

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Bill Shaver

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