How to identify the terminals on a 4 terminal Voltage Reg...

chappie

Member
I posted on here a week or two ago about the generator on my Allis D17. I posted a followup to the same thread but no one has replied. I guess the thread got old. To refresh you're memory, it's reversed the battery polarity, and is now a NEG ground, rather than a POS ground like it should be. I'm just going to leave it that way, and just charge the battery as it is now. Come Spring, I plan to replace the generator with an alternator, but for now, I just want to polarize it, so I can move it to a better place, since it's blocking part of my driveway.

Anyhow, I know what to do now, but I'm still puzzled how to polarize the generator. The reason is because the regulator has no markings on the terminals, or if it did, it was painted (Allis orange) so the markings are lost.

My voltage regulator (VR) has FOUR terminals. Three on one side, and a single one on the other side. Do any of you have a drawing which you can post, that shows which terminal is what? I was told I need to jump a wire from the BAT terminal to the GEN (or ARM) terminal. The VR does say Delco Remy on it's cover, but that is all I can read.

I read this on a webpage: "To polarize a generator? Before starting the engine, momentarily touch one end of a piece of wire to regulator terminal marked 'arm' or 'gen' and the other end to terminal marked 'bat'. A spark will occur when wire is removed this is natural. DO NOT TOUCH 'fld' terminal, regulator will instantly be ruined."

If I cant identify the VR terminals, is there any reason I cant run a jumper from the battery (non-grounded post) right to the generator (GEN or ARM) terminal. *(If they are marked)*. We're having a severe cold spell, so I only took a brief look, and could not see any markings on the genny either. But it seems like it would be easier to just use a longer wire and go direct, because the VR is sort of buried with a rod in front of it. And then there are FOUR combinations, rather than just the two on the genny.

Is there any way to identify which terminal is which on the genny? I know if I get it wrong, I'll ruin the VR, so I want to make sure I get it right.

Thanks for all help!
 
Don't know how much help I can be, but every VR I've seen the single terminal you said was by itself would be the Gen, again all mine if you are holding the VR with the three terminals pointing toward you the one on left would be the L, the middle Bat, and the one on right would be the F [ field ]. Don't know what you have but if its 6V a lot of the VR are for POS ground systems only, as for the Generator if you cant find the A or F on it there maybe a way to check it with a ohm meter, don't think I've tried it, if you have a another one laying around you could check it, if not someone else on here maybe able to tell you, or I could check one tomorrow, I know if you ground the field it will put out full charge, and you know you can just leave it disconnected and move your tractor wherever you like to, good luck. Mike
 
I have never seen a VR that did not have the terminals marked. You may have to remove the wires from the terminals and clean the terminals with a small wire brush to read the markings.
 
You said I can move the tractor with the generator disconnected. Do I just remove the wires (or one wire) from the generator, tape these wires, and run the tractor off the battery? That would at least allow me to move it now, until the weather is better.

Thanks
 
If its a Class A Voltage Regulator this may identify the terminals

Put one ohmmeter lead to the VR metal case/frame on low ohms scale:

BAT terminal should have near infinity ohms IE and open circuit
GEN/ARM terminal could have in the 20 to 50 ohms range as that's the cutout relays shunt winding
FLD terminal should have low resistance, maybe near 0 to 5 ohms.

On some 4 terminal VR's, terminals LOAD BAT FLD are side by side while GEN/ARM is underneath or on one side/corner all by itself

To test the generator itself independent of the VR, dead ground the FLD post to case/frame for full max charge condition, and connect GEN/ARM post to hot ungrounded battery post (via ammeter is fine)

BEFORE starting Polarize genny by momentarily jumping its BAT (or any hot ungrounded battery voltage source) to the GEN/ARM and you should get a small spark

John T
 
On the generator and regulator, the GEN and BAT terminals should have heavier wires than the F (field) terminal. You can identify the GEN and BAT that way unless someone has rewired it incorrectly.
And yes you can run the tractor just off the battery just fine.
 
The will be an "A" or an "F" stamped next to the terminal studs on the generator. Might be a bit covered up with paint, but I've never never seen one that wasn't marked.

<img src = "http://www.earlycorvettes.com/corvettesite/53to55Parts/chassis/generator/pt1102793.jpg">
In the photo, the "F" is clearly visible, lighting hides the "A" a bit.

With this "A" circuit system, there's no problem jumpering from the battery to the "A" terminal at the generator.

Almost without fail, the regulator terminals will be labeled, as well, take a close look.
<img src = "http://www.studebakerparts.com/studebakerparts/store/s/html/images/reg005.jpg">
 
My generator looks identical, except it's black. *I like your red one :)
They never stamped the A and F in mine. I looked closely, and cleaned around those posts. However I notice in your picture that the "A" post is thicker than the "F" one. Mine also has a thicker post, and that is the BROWN wire, which according to a wiring diagram, is the ARM post. The FLD has a GREEN wire. Either they forgot to stamp mine, or they just dont stamp all of them.

Your Regulator picture appears to be a 3 terminal type, rather than my 4 terminal. But at least I now know where to look for the labels. (When it's warmer outside).

Anyhow, I believe I can just run a jumper from the non-grounded battery terminal to that "A" terminal on the generator to polarize it. Because of the tight space around the VR, I think it'll be easier to go right to the generator post.


Thanks
 
I already gave you a test to see which VR terminals are what and as I said the GEN/ARM terminal is often on one side or corner or underneath all by itself.

On the Genny the ARM post is often bigger then the FLD post

If you measure to the gennys case frame with an ohmmeter the FLD will be a few ohms (maybe 2 to 6) higher then the ARM post which will be very low ohms.

The gennys output is on its ARM post with respect to case frame ground and if you dead ground the FLD to case frame that is the max high charge condition. If you connect the ARM to battery via ammeter and ground the FLD post it will charge if the genny is any good at all.

Jump any hot ungrounded battery voltage source (like at BAT on a VR) to the gennys ARM post to polarize the genny

GOT IT NOW?????????????//

John T
 
I took the wiring diagram, processed it using a paint program, and made the wires the color they are supposed to be. Here's the final result.
 
My picture did not upload, I'll try again.
a211918.jpg
 
The drawing is correct for 4 terminal VR's

BAT to ammeter
LOAD to lights and ignition to supply hot voltage source
FLD to gennys FLD
ARM to gennys ARM post

John T
 
Before you try to polarize your genny, remove the VR and check the underside of it. Many are stamped whether to be used for Positive or Negative ground. Some don't care.
Just disconnect the heavier wire and run the tractor with it disconnected. this will not be a problem. Bob
 

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