Farmall H-DisCharging

Dave42H · Sep 10, 2009

I have a 6volt system,8volt battery,a rebuilt generator,a 5yr old regulator with low hrs.
I"ve cleaned and polrized and everything else I can think of. It will charge a little on full throttle, but at low idle it"s doing a heavy discharge. Any suggestions

rustyfarmall · Sep 10, 2009

The generator is a 3 brush unit. The third brush is adjustable. Moving that third brush closer to the next closest brush will increase the output of the generator. You will have to remove the cover at the rear of the generator so you can see that third brush. The head of the adjustment screw is visible on the outside of the rear frame. You might also need to adjust the voltage regulator, but I'd have to find my manual before giving the procedure on the regulator.

redblood · Sep 10, 2009

On my H with an 8 volt battery would not charge till battery was discharged to I believe 6.5 volts.
Put a new 6 volt battery in and all works properly.

Only took me 1 month, 3 voltage regulators, 1 rebuilt generator and 5 minutes talking to an older 60s-70s man to tell me how to fix it.

Or adjust voltage side of regulator to see higher voltage and turn on.
On the tractor talk side there is a post about this right now.
Joe

pete 23 · Sep 10, 2009

System should never show heavy discharge at low idle (unless you have a load on such as lights) as the cut out should disconnect gen from battery. This is a problem with using 8 volt batteries, cut out needs to be set above the static 8 volt battery reading of approx 8.4 volts and charging voltage set on regulator portion to approx 9.2 volts. Most people do not have the knowledge of how to do this and although it can be done without special equipment other than a multi meter you have to know what you are shooting for. You need a fully charged battery to start with so voltage will rise to the point where it can be regulated.

Bob M · Sep 10, 2009

Sounds like a failing voltage regulator...

Test by temporarily grounding the regulator's FLD terminal with the engine running at governed RPM. If the ammeter now shows a strong charge (15 amps or so) the problem is the VR - specifically the contact points on the regulator relay.

If grounding the FLD gets a good charge you can try gently cleaning the points with an ignition file or emery paper - it may solve the problem. (Note - the regulator relay is the relay with its contacts held CLOSED by spring pressure). However if that doesn't work a replacement regulator is the next step.

Note also unless a 6 volt regulator is adjusted for 8 volts it will not properly charge an 8 volt battery! Better to address the need for the 8 volt battery in the first place (most often inadequate battery cables) and install a 6 volt battery.

Farmall H-DisCharging

Dave42H

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rustyfarmall

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redblood

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pete 23

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Bob M

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