1948 - 1956 F1, F100 & Larger F-Series TrucksDiscuss the Fat Fendered and Classic Ford Trucks
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Okay... 56 ford charging system. Good generator (gone through) Brand new voltage regulator. Its wired correctly. I wired it how the book says. It charges great.. too much. It starts to smoke the back of the voltage regulator. I think its that little diagonal strap on the back. I tried grounding the voltage regulator case to the battery terminal and it didnt change anything. It didn't run very long like this. I dont want to burn it up. Is it a ground issue? Bad voltage regulator?
The straps are wirewound resistors, no? Check carefully, sounds like something is wired incorrectly, but you say "how the book says". Hm. Possibly the regulator is out of adjustment or defective. Is it NOS or?
There are three windings - cutout, voltage, and current. Usually they are set reasonable. Have heard of generator itself slinging solder when passing too much current.
What are your voltages at 2000 RPM, say? I'd be inclined to back off on the current as WAG.
I have had new regulators be way out of adjustment. Years ago I simply found used regulators in junked cars and swapped out until I found a good one. These days I carefully adjust the new regulators for both voltage and current.
The Ford shop manuals are a little tough because they had proprietary test equipment that isn't so easily deciphered into a DVM (for me anyway) plus they won't tolerate a 30 amp load either.
Ended up setting the voltage and then, when still not charging adequately after a good run, a guess and by golly tweak or two with the current part of the adjustment did the trick. There doesn't seem to be a lot of fine voltage range adjustment possible anyway, either "not enough" "way too much" and "ballpark".
It looks to me that the problem back in the day had to do with the generators inherent problem of not charging at idle RPMs. What that meant in practice was setting the regulator a little "hot" for driving around town with short trips and stop and go. This worked fine, but a long trip meant boiling out a battery.
I adjusted for current by carefully bending the tab the middle spring pulls against. A small movement in the tab is a large change in current.
I set my regulators the following way:
1 - run the car for a good long time to get the regulator warm.
2 - turn off the car, disconnect the battery.
3 - remove the cover from the regulator.
4 - make a very small adjustment in the spring tension on the current regulating coil (the middle coil on Ford voltage regulators).
5 - reconnect the battery.
6 - turn on the headlights.
7 - start the car. rev the engine up, turn off the headlights, and observe the maximum current on the ammeter.
8 - repeat steps 2 through 7 until disgusted or satisfied. I usually achieve satisfaction in about three adjustments.
Before voltage regulators came out you adjusted the third brush on the generator. The third brush provided the current for the field coils. If you set the third brush for night driving, you had better run your headlights in the day too, or you would boil your battery dry.
How did you/what are you measuring the current with, though? My DVM, a good one, is not rated for 30 amps, it tops out at 10. But the manual sez adjust till 30 amps. Setting the charge voltage was OK, after adjusting for temperature. But it wasn't getting charged adequately.
So just kept tweaking the current up a bit at a time till the battery was fully charged after returning from a long drive at highway speeds.
Discovered corroded connections anywhere in the path make accurate adjustments impossible. Battery needs to be fully charged to start with, and always blip the throttle before checking voltage after any adjustment.
There aren't too many Elmers left who remember this stuff hardly. Found the spring adjustments are pretty touchy and best to make any adjustment in the tightening direction, just like a guitar string. In other words, if the voltage is too high, take it down below the desired setting and stretch the spring back up tight.
Tough to say remote troubleshooting. Have a shop manual? As a practical matter, have another regulator to try?
The cutout relay points will stick sometimes. Not sure if that will fry the regulator, but it will release the magic smoke from the generator, because the battery voltage backfeeds.
Sometimes you'll see dents on an old regulator cover. This is because of the field expedient way to unstick the cutout - bang on it.
This is the point where someone will come along and suggest a GM one-wire alternator, and ditch the whole thing, but I was always waaay too stubborn for that and wanted to learn this area of obsolete tech.
Well.. Like I said, it is a new regulator.. Could be junk, who knows, but I dont have any other 12 volt regulators to try. I paid around 70 bucks for this thing. (dont ask me how i feel about that) It will start to smoke within 15 seconds after its at high idle and it charges like hell. Which I think is odd for low RPMs
What I try to do is read everything I can get my hands on about a given area of study on these beasts. The Ford Shop Manual, Motors Manual, and good ole internet search is great for this kind of thing.
Lots of webpages, forum discussion and general info on DC generator charging systems. They are all similar, with some important differences. Take the time to familiarize yourself with the components.
Is your GEN light illuminated when this happens? It will be if your cutout is stuck, iirc. As a WAG, one of the windings is sticking anyway.
(Also, what happened to the original regulator?)
The cutout relay should not engage till well above idle. You can then watch the points separate again when RPM speed comes back down to idle.
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