Couple questions re H

DD in WA · Nov 30, 2019

I'm going to rewire a 42 H I got from my wife's uncle a few years ago. Couple questions:

1. Should the F generator terminal be connected to the F regulator terminal? Now it's just tucked between the regulator and the generator. It still has 6V system, no headlights so no light switch with the ammeter. Suspect originally had a mag but now has a coil and distributor.

2. There doesn't appear to be a fuse anywhere in the wiring. Shouldn't there be? If so, where should I put it and what amp fuse?

Janicholson · Nov 30, 2019

The regulator is not a regulator it is a cutout only. The F terminal on it attaches to a resistor that causes charging at about 3 to 5 amps. This is enough to
keep the battery charged as it has no lights. So, from its looks, I would replace the cutout and make sure it has the three terminals as this one does. The
generator will make an effort to charge if you ground that F terminal on the generator (tests the generator) if it is good. Jim
This should link to charging analysis from John T

rustyfarmall · Dec 1, 2019

Good luck in finding a NEW cut-out relay.

BarnyardEngineering · Dec 2, 2019

The only fuse on these tractors was for the lights.

Jim Guarino Agri-Services · Dec 2, 2019

As mentioned in the other posts, you have a cutout relay. Also as previously mentioned, on a tractor without a light switch, the field terminal on the cutout relay is connected to the "F" terminal on the generator for a low charge rate. For a higher TEMPORARY charging rate, the field lead is removed from the cutout relay field terminal and to one of the cutout relay mounting screws. The charging rate is also adjusted by moving the 3rd brush holder to move the 3rd brush closer to, or further away from the fixed brush. If the generator is operated in a high charging rate for too long, the battery will be overcharged, and will spill acid out of the vent caps. Besides replacing the cutout relay, I suggest taking the generator to a rebuild shop to have it cleaned up, tested and adjusted. I have purchased good original cutout relays from Jensen Tractor in Askov, MN. You could also mount a regulator in place of the cutout relay. The Farmall H operator manuals from the later 1940's to the end of production, have a pretty detailed explanation of the cutout relay system.
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Couple questions re H

DD in WA

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Janicholson

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rustyfarmall

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BarnyardEngineering

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Jim Guarino Agri-Services

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