nuther gen question

Was reading today in Delco Remy Service Bulletin IG-150 where it says, with 3rd brush generators, no voltage regulator is needed. What happens if a voltage regulator is installed on a 3rd brush gen?

When buying a rebuilt generator, I've never been asked if I want a 2 brush or 3 brush type. As I study IG-150, there is a lot more to this stuff than is apparent to the less-than-fully trained!

no regulator? never heard of that before -- might have to google that one -- LOL -- Roy

Ron to some extent a three brush is somewhat self limiting and you can further limit output by moving the third adjustable brush FARTHER from the fixed non grounded brush. The early units (NO VR but ONLY a cutout relay) used a manual Low High charge switch often incorporated with the light switch while the later 2 brush systems used a full fledged voltage regulator.

John T

The early 3 brush gennys used a simple cutout relay and a manual Low High charge switch and DID NOT have a modern full fledged Voltage Regulator.

John T

John, Thanks.

Care to comment on my question about what happens if a voltage regulator is used with a 3rd brush generator? Bad; Good or no matter?

Like on the WC, WD, WD45 AC tractors? That was a 3 brush? Generally we put the switch on low throughout the summer, and on high during the winter months, when it wasn"t used as much, but had harder starting in the cold.

Being poor / cheap, on these old tractors a good cut out cost about as much as a voltage regulator, I would pick up an old discarded regulator and use the cut out portion and all folks thought I has installed a regulator. All regulators had a cut out relay built in

What we really want to know is if a regulator can be used so we don't have to guess with the manual control and either over or under charge the battery? I want to take the guess work out of the equation.

Many a 3 brush generator is equipped with a regulator. IH switched to voltage regulators on their Farmall tractors in about 1950. All H and M's up through the 450 used a 3 brush generator. It was somewhere in that time frame of the 450 where all replacement and original equipment generators were switched to shunt wound (2 brush) as I installed a few when original generator was beyond repair. All 560 etc were two brush and from then on up. I will add that a different field coil was used with the regulated generators than the generators controlled with a high low charge switch. The ones with regulators had less current flow through the fields. That is a problem with a lot of rebuilt units as they go by one size fits all. I will add that the two unit voltage regulators are a combination current and voltage regulator. Thus they use a fourth terminal for light load so that portion of the charge is not subject to the current regulation portion of the regulator. Not a good system as even a Delco Remy representative confessed at a service conference once upon a time. It wasn't until the 06 series IH tractors that they started to use the three unit regulator which was far better. It had been used on Motor trucks and automobiles for many years.

If you have a friend with a Model A Ford take a look at the generator. That little can on top is a cut out. When the engine starts the generator generates enough voltage to pull in the little coil inside of that cutout. Also one of the brushes can be moved back and forth to set how much amperage will be put out. Crazy simple.

'44 2N : Dad said"If you're cultivating or raking hay all day,turn it down,If you're just"choring" turn it up!"

John T What would happen if you took the wire off the 3rd brush and put it on the hot brush next to it & then wired up a 3unit regulator?

Jim's Opinion (mine) is that it hurts nothing to run a regulator on a 3 brush gen. If it is movable, move it as close to the fixed brush as possible, and go from there. Do not use the light switch control at all. the regulator only needs to charge at 2 volts over on a 12v system, and one volt over on a 6v system. The regulator with a current limiting voltage relay (common in mid 50s delco) should be set to limit charge to 15 to 20 amps max. Jim

Ron, I would have to go through all my archives to be 100% sure BUT I think towards the end of the 3 brush genny era they were using full fledged voltage regulators on some 3 brush gennys. Of course in the beginning it was the three brush where you manually had to set the light switch for Low or High charge while the two brush and VR's was the new n improved method. I think if I were going to use a VR on an old 3 brush genny, I would adjust the third brush (if its adjustable) to the max charge condition as close as permissible to the fixed main non grounded brush and then if matched let the VR do its job of regulation. The VR's field current control relay and its onboard fixed wirewound resistor is supposed to set there and switch and chatter to control the gennys output versus the batterys state of charge and its supposed to be designed with the current ratings of the field windings in mind so as to NOT overheat them. However several 6 or 12 volt gennys had close to the same field winding ratings so perhaps different if still close VR's would still work even if not perfect.

John T

I agree, the VR's that had three coils, Cutout, Voltage Regulation and Current Regulation are superior to the two coil, cutout and combo current and voltage. I didnt check my archives but believe Deere also on the later 3 brush genny systems also used a Voltage Regulator

John T

Id say your method will work as long as the field current rating isn't exceeded. Thats how a 2 brush is wired anyway, the fixed non grounded brush wires to the ARM post with no 3rd brush interception.

John T