Farmall Generator Cut Out

38F-20 · Dec 31, 2011

I've talked with another person but want to get some others' opinions. Can I use a 6-volt cut out relay on a 12-volt negative charge generator? I know the cut out just disconnects the battery from the generator so I thought that I should be able to. I just want to confirm this thought before I try it. Have a happy New Year.

CNKS · Dec 31, 2011

No message.

Jim Becker · Dec 31, 2011

If you are talking about just a cut-out, not a regulator, the generator will probably charge it OK. However, I'm not sure that once closed the cut-out relay will open when the engine is shut down.

Most 12-volt generators will badly overcharge a battery if there is no voltage regulator.

38F-20 · Jan 1, 2012

I put 12-volt field coils in my generator and need a cut out to be original for the time period. I'm going to try it anyway and see if it works. Thank you for all of your help.

gene bender · Jan 1, 2012

All the cut-out does is close thepoints when the gen is charging and then open when no voltage is at the gen terminal. Does your gen have the adjustable third brush cause if it has the cutout it should have it. Positioning the third brush does affect the charge rate the cutout doesent do that.

teddy52food · Jan 1, 2012

The points will close at a little over 6 volts and the battery will discharge until the voltage gets up to + 12. Watch the ampmeter as it maybe won't open at shut down. Increaseing the air gap and spring tention may help.

Janicholson · Jan 1, 2012

It will not correctly release at shutdown, and needs to be a 12v. It is volage sensitive for hold in. Best option is to gut the old unit on the inside and put a 50 amp 100 piv diode in its place. Hook it up so the band on the diode (direction of non conduction) is toward the gen. This prevents flow from the bat to the gen just like a cutout, and looks the same. Jim

Owen Aaland · Jan 1, 2012

(quoted from post at 13:53:40 01/01/12) It will not correctly release at shutdown, and needs to be a 12v. It is volage sensitive for hold in. Best option is to gut the old unit on the inside and put a 50 amp 100 piv diode in its place. Hook it up so the band on the diode (direction of non conduction) is toward the gen. This prevents flow from the bat to the gen just like a cutout, and looks the same. Jim

It may be possible to open it up and readjust it for 12 volts but Jim's idea of a diode is probably a better way to go. The only downside of a diode is that it is polarity sensitive while a cut out will work either positive or negative ground,

Janicholson · Jan 1, 2012

The diode can be put into the old housing either way (it is isolated from case contact ground, so putting it together correctly (and marking the underside) will be just fine. Jim

38F-20 · Jan 1, 2012

Thank you for all of your input. I bought a 6-volt cut out a few years ago, and didn't know if it would work on my system now. So basically, I should either use a 12-volt cut out or a diode to be sure that the battery is disconnected from the generator.

I was going to use an original 4 position switch off of a Farmall H to use the low charging setting all the time. Is there still much risk of overcharging the battery without a regulator by using this method?

Janicholson · Jan 1, 2012

The low charge position charges at about 4 to 5 amps. (if the third brush is adjusted correctly) thus it absorbs ignition current, and a little for the battery. The High charge position is to establish a recharge of the batery and will need to be turned to L after about 15 minutes of work. A skill of the operator is to know when to do so. Jim

Farmall Generator Cut Out

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gene bender

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