Voltage regulator, generator wiring (12 volt)

[burly]

Hey guys, attempting to replace GM alternator with a 1940 - 48 generator that's been converted to 12 volt with the 3 original ground, field and armature terminals. My question is the 12 voltage regulator (BW R295) supplied has 4 prongs marked I,A,S and F. I know where the A and the F go, not sure on the I and S. I guess one of those 4 is battery? Also wonder about ground wire from generator location? Unfortunately the gentleman that converted the generator has passed on and the voltage regulator instructions only refer to a plug in as I guess it was designed for. Thanks fellas! Trying not to fry anything!

[alchemy]

I’m no expert on wiring, so I just bought a 1960 Ford regulator (three tabs) and wired it as if it was in a ‘60 Ford pickup. The ground wire from the generator is ran all the way to the mounting screw on the base of the regulator.

[burly]

Thanks alchemy! Wonder how well the voltage regulator itself must be grounded? Just bolting mine to firewall.

[pistonbroke]

I don't know the regulator you are referring to but when I have done this in the past I used the 1956 ford regulator . It is a bolt on for earlier fords. Tim

[fordyford]

The regulator you described is for an alternator and will not work with a generator.

[Automotive Stud]

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Fordyford is right, that's the wrong voltage regulator it's not going to work with a generator. You need a Napa VR414, with the A F B terminals. It's for a 57-60 Ford and should bolt on in place of the original.

[pistonbroke]

On the same note, did you guys know if you save the box O'reilly auto parts will give you a life time warrantee on their regulators? I have one for all my old rides. and have used the warrantee once with no questions asked. Tim

[burly]

Thanks guys! Appreciate your responses.

[burly]

Guys, got the correct voltage regulator wired up and it appears to be charging. Would any of you fellas know what gauge the ground wire from the generator to the voltage regulator should be and will grounding it to one of the voltage regulator cover screws be adequate? Thanks again.

[pistonbroke]

I can't say it's factory but I have always ran 10 gage. Most of those regulators have a ground screw in the side of the base but the cover screw would work in a pinch.

[burly]

Thanks!

[rotorwrench]

The early voltage regulators were mounted on rubber bushings so that the buzz of the VR pole wouldn't be detectable. This required a ground of the VR case to the system so they took it directly to the generator. In later years, they stopped using isolator mounts on the voltage regulators so they did away with the ground. They had B for the cut out to the battery, A for the armature output, and F for the field feed.

An alternator can be controlled in in several different ways and it has to have an exciter through the alternator out warning light. It uses a gang of diodes instead of a cut out.