Identifying generators and matching regulators

Working on a couple of 6v positive ground generators for my tractors and need some help.

On one of my tractors [Co-op E-3], the generator works and charges with field wire grounded, but nothing otherwise. I think I need to replace the regulator, But the generator does not have a tag. I do know it is a 3 brush generator. I don't know if it is the original 3 brush generator.

How do you identify the generator to order a regulator?
How closely do you need to match a regulator to a generator?


My Moline UTU has a bad generator, also without a tag. It fails the motoring bench test. I have a good generator, a Delco 1102667, that tests and spins well to put on it. I have Googled the good generator, but all I find are panel mount regulators for mounting on a car firewall. I would like to find a saddle mount regulator.

How do you match a regulator to this generator?
Does it matter that this is a 2 brush generator when ordering a regulator?
Should I have the bad generator rebuilt (Which I am sure is not original to the tractor.)?

In the past I have sent my generators out to a local repair shop, but the last time I was less than happy with their work and what they charged. There does not seem to be anybody working on these anymore so I was hoping to try and fix this up myself.

Thanks for any help.

Hope this info helps: I have a new old stock COOP generator, paper tag reads possibly TO-7521, unsure of last 2 digits. Generator tag stamped Autolite GEO 4818A-3 5D, This generator has a cut out relay mounted on it with a wire coming out of the generator body hooked to the underside of it, and a terminal coming thru the generator body with a nut on it for hooking a wire to it that I assume is the field lead, this lead is grounded on my running E3 as it has been before I got it 30 years ago, I believe there was a wire going to possibly the light switch to control charge rate originally.

I have a couple of E3s and an E4. I will look at them later today and post back. Mine have had the gens replaced and have two charge regulators. They originally had only a cutout relay and not a regulator. The armature post on the gen went to the cutout. The field post had a wire from the light switch to control high or low charge rate. If you have an I&T manual it will give you the numbers. I'll check mine later today.

30 before SN 31196: gen GEO-4818A3 and reg CB-4014. After SN 31195: gen GHD-6001F and reg VRR-4102A

One of mine has been changed to a Delco and both have 2-charge regulators. Those old generators were low output. I think any 6V POS ground reg would work.

Assuming that the generator for my Co-Op is an original Auto-lite, does Yesterdays tractor here have a regulator that would match it? They don't have any regulators listed for Cockshutts.

At steiners they have a regulator listed for Cockshutt 30, but also a conversion kit when replacing a Cut-out. What is the purpose of this and do I need it?

Is there a difference between regulators for a 2 brush vs 3 brush generator?

The Delco 1102667 that I have and want to install on my UTU, what regulator here would match that?

Thanks for any help.