For the last couple years I’ve been working on recommissioning a 1945 Willys MB. One of the last pieces of the puzzle is getting the charging system operational. The MB was originally a “B” circuit. I have a CJ gen and regulator set up for “A” circuit. The pair just spent the last 3 months at the electrical repair shop (closing this year as the old chap is retiring.) Short story long, I put it all together and couldn’t get it to charge. Finally after polarizing it a couple times I got it to do its thing. He said it was putting out 100 amps (which seems like a lot?) Anyway after I finally got it to start charging it basically pegged the ammeter but then settled down and it had been fine the three or four times I drove it around. Then, the last time I took it out it seemed to stop charging. I tried to re-polarize it but still nothing. It shows a draw on the meter when you turn on the lights, etc. so I believe the gauge is good. I checked all my grounds and everything seems OK. The wiring is all brand new. The battery is good and fully charged. I’m not sure if the regulator is bad or the generator or what to even check? Any insight is always appreciated! (I know the wire terminals are a little big but I didn’t want to cut my expensive reproduction harness. I mounted the regulator low so I could hide it with the huge wartime one that mounts above.)
If I remember, the A circuit-B circuit thing on an alternator had to do with how the field circuit was grounded. One version was grounded internally and the other ran a ground lead back to the voltage regulator. I think. Maybe it's a similar issue with DC generators. Many years ago I swapped out the alternator on a '64 Plymouth with an external regulator on the firewall. To get it working properly I had to make up a ground jumper wire, feed it outside of the case and ground it under one of the alternator case screws. I'm likely wrong about your particular issue but somebody here should be able to straighten me out and get you on the right track.
I appreciate the reply! This is driving me bananas. I tried to repolarize again today but doesn’t seem to have made any difference. As far as grounding, that flat ground strap you see in the pics goes from the case of the gen to one of the mounting screws of the regulator to mount it to the fender. The original B circuit genny would have been wired like this so that’s how I did this one just thinking it probably needed to be grounded since it was rubber mounted? Though I guess, technically, it would also ground through the tension arm? I’ve found so much conflicting information on the Web… myhead is spinning…
Here's a little bit of info that might help to sort things out. https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=nboard&th=439293
I did some tests on the generator as described and it seems to be putting out 7+ volts. I’ve sourced a new voltage regulator and it should be here this week.
That’s a two stage voltage regulator, it’s used on 3 brush generators where the field is controlled by adjusting the movable third brush in the generator. You need a 3 stage (coil) Voltage regulator for the generator you’re using. If you switched over to A circuit a Delco regulator will work with the Auto-Lite generator you are using. With no field control the generator could have charged wide open and threw the solder out of the armature. You can disconnect the field wire at the generator and ground the field post with the engine running, rase the rpm’s and check voltage with a volt meter and see if the generator charges. If it does your good, get a new regulator and try again.
Yes the new regulator I got has three windings like all the other coils I’ve ever seen (until the shop sent me home with that 2 coil one?) Hopefully I didn’t damage the generator but it seems to be working again as it should the three of four times I have started the jeep. Thanks for the reply!
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