The Stovebolt Site Forums The Shop Area The Electrical Bay 12 volt generator not generatin....

I re polorized a 12 volt generator i got from a junkyard and stil no charge.That is if the gen light is working properly as it stays lit.The battery has been on the charger all day and starts the car fine.Can my local parts store bench test these?This is my summer cruiser and once the snow and salt are gone is my daily driver.Its on a 59 235 in a 60 chevy sedan.Never pulling one apart before are the brushes easy to replace? Thanks...Ron

I'm going to take the liberty of copying this thread to the Electrical Bay. I suspect Randy can probably answer your question.

Yes, your parts store should be able to bench test your generator. You don't have to be a rocket scientist to work on them, either. Follow the instructions in the shop manual to work on it. If you search this forum you should find instructions on how to test the generator and determine if it is the gen or the voltage regulator that is your problem.

Thanks fred, ill take it in.I dont have a manual for it .While im not a rocket scientist,its doing it that first time.Ive broke enuff stuff to know to ask first.I have a problem geting things from books to my hands but show me once and im good to go.Ill get it tested and get a set of brushes to put in.Is there any thing else recomended when giveing these a tune up besides brushes? Iput in a new voltage regulator when the problem ocured so my problem is either fryed wireing or the generator.Thanks... Ron

There is a simple procedure to determine if your generator is at fault...or the regulator? Get out your trusty dusty jumper wire and connect one end to the "Field" post of the regulator, and the other end to the engine block. This will by-pass the regulator, to see if the generator is working. If you increase the engine rpms and the output increases the amp gauge will show a positive charge, or in you case the light goes out, the odds are better than average that it is the regulator, that is at fault.

In contrast....If there is no increase in output remove the ground connection from the engine block and strike it against the block. If you do not get any sparks, that will confirm the generator is not working.

Who says you gotta have a fancy smancy meter to check you generator and regulator output?

By the way....rumor has it .....only the **** owners own and use pink jumper wires.....I hope you are not one of those......Randy

Well Randy,you must be part psycic... cause yes im a **** owner.Its ok though.Its an old **** .1972.It what i drive in the winter as a sacrafice to the rust and salt gods of the northwoods.Igot up early this mornin and took them both to the local napa store and it took a while of book looking and he dissapeared with them both.He came back 5 minutes later and said WICH WAY DO THEY TURN.Isaid around and around.It was then determined that they turned clockwise and away he went again.He put the first one in turned it abought 30 seconds and brought it back and said it was bad and kept triping his circuit breaker.Iheard him try the other one 4 times and said it was only puting out 11 amps.Iasked him what i needed to repair it and only got a blank look and a dont know, there before my time for a reply.I took them to a shop where i new the gentelman would be able to repir it.This guy is sought after all over the country to do repair work.He made one out of the two cleaned,put in new brushes,and reground the comutator[ i think thats what its called]and tested it on a machine that was made for just that purpouse. It was abought an hour and a half of labor and new brushes for 63 dollars.More than i wanted to spend today but a good deal in my opinion.It only gets better from there.While iwas there i ran into a fellow that i met at a car show who owns a 41 chevy and asked how my 42 chevy was comeing along.Iexplained that my frame was done and im stalled out untill i can get some holes patched that the previous owner chiseld in the cab to install a heater .To make a long story short hes comeing over on monday and take a look and either patch it in my shop or well haul it to his.At any rate i want to thank you for your reply and i am going to print it out and put it on file in my shop for future reference as i have three vehicles with generators.Do these same procedures work on the 6 volt ones as well?Thanks for your input...Ron

Same generator, different windings. In the early 70's we rebuilt them in our shop. Had a bench just for generators/alternators/starters. Small lathe to turn the commutator, wheel to redo the slots on the commutator, growler to check the armature and a meter to check the coils.

Fred, thats pretty much what this fellow did.Unfourtantly i still have problems.Iusedm randys test method and by pased the regulator and the generator light gos out.The regulator was the first thing i changed when the problem ocured.Would haveing a bad generator fry the new regulator?Also there are two[i cant think of the name,litle silver batery shaped with one wire...resistor?}One is on the regulator and one on the generator.What lead should these be hooked up to and would the lack of these cause my regulator to not work?Any and all sugjestions are greatly apreciated...Thanks Ron :mad:

You want to be sure and polarize the generator to the regulator after you reinstall it. The procedure for **** and Chevrolet are different. For the Chevy, just strike the battery wire and the armature wire together using that same trusty jumper wire you had before. You should see a spark when you do that, if all is well. You can also spread apart slip joint plier handles and touch the two posts like we used to do here in Kansas. Pliers are good for everything here in Kansas from regulator polarizing to hitch pins for tractor implements.

As for the **** generators....you need to REMOVE the field wire from the generator and strike it on the BATT terminal of the regulator. Again, you should see a few sparks when you do that, and all is well.

The difference in the procedure is determined by where the field coil wire is connected inside of the generator. If the generator field coil wire is connected to the INSULATED brush you have what is called and "A" circuit charging system. Most GM products for example.

If you have a "B" circuit the field coil wire will be connected to the NON - INSULATED brush or ground. Most **** products for example....

And now you know as much as I do......Thanks Randy.

Randy your test made the light go out so i asume my regulator is either bad or improperly installed.i have two of thelittle silver thingies with one wire atached.i beleive there som you dont get static on the radio,i just cant rember the proper name.What terminal on the gen and reg do they go on or do i only need one. Thanks... ron

the delco style generators and regulators need to polerizzed.
jump between the batt terminal and the armature or gen terminal at the regulator make a spark that should set the poles in the right direction

Rider, I had the same problem the the 6v gen in my 46. I didn't want to just change parts until it was fixed, I wanted to figure out why then gen wouldn't -erate. Well, to make a short story, long, I changed the brushes, cleaned the commutator, even put a couple of drops of oil in the oil cups, polarized, repolarized, maded some sparks with a wire and was about to give up when I decided to remove the brand-new looking regulator and found out that the resistors on the back of the reg were toast. The best I can figue is that whoever put the reg in before I bought the truck had the wires reversed on the generator. I didn't do it, I swear! I put on a new reg, made sure the wires were right on the gen & the reg, re-re-repolarized the gen and voila, juice! Anyway, check the back of the reg to see if the resistors are burned. Best regards, Jacques

I'm printing this out and takin it out to the garage.
Adios, Kip

Ok....I have all of test info and the polorization info printed on a post card ready for your shop wall. It has a cute 50's pinup picture on the reverse. Send me a SASE and a buck and I will send you a couple. It will make your garage look good, your tool box even better and it will impress the heck out of your wife and her friends...Randy

OK guys,
I posted the questions on changing a generator to an alternator before I read down to all this good advice. I hate to show so much ignorance on this matter, but I have a pile of quesions for you all. First, I have three wires going to my generator, which one is the field wire? Also, I was told that with alternators you could do a quick check to see if it was good by dis-connecting a battery terminal and seeing if the engine dies. Is this true, and does the same apply for testing generators? Does anyone know of a good book with information about this kind of stuff? I know, lots 0f questions from a newbie, thanks all,
Bo

SHocking!,,,,Just Shocking!!!

You can check to see if a GENERATOR type charging system is working by disconnecting the battery cable. If the vehicle still keeps running chances are good things are working. If the vehicle engine dies whenyou remove the battery cable from the battery either the charging system needs some attention or......you ran out of gasoline!

DO NOT remove the battery cable from the battery to check an ALTERNATOR type of charging system. You will likely be shopping for a new alternator. The stray arcs and sparks created when you remove the battery cable will burn out the solid state compoents inside the alternator, like the diodes and the regulator.

Instead just place a flat screwdriver on the smooth bearing surface on the back of the alternator, while the engine is running. If the alternator is charging... this surface will be magnetized. If you still have doubts turn on headlights, heater blower motor etc to increase the electrical load. Then there will be little doubt.

A snap-on red handled screwdriver number 7 works best for this test, but in a pinch a Craftsman clear handled number 4 will get you by. If you have neither of those just use the blade of your brother-in-law's pocket knife. If you have none of these, carefully and quietly sneak into the house, go to the kitchen, get into the silverware drawer, and grab a silverware knife.

If you get caught, no one on this board knows you... or has ever seen your truck before.

You are a redneck if...

You check your alternator with a sharp knife with the engine running.
hahaha

I thought your doctor told us to keep you away from sharp objects,,,,especially mixed with electricity!

IM GUILTY ive checked alternators by removeing the cable.So my question is what year did they start useing solid state dohickeys in alternators? Ihavent fryed one yrt but maybe i just got lucky...

Most all alternators since their birth have had at least some solid state parts inside like the diodes for instance and regulators followed soon after. Slow Rider you must be one of those lucky ones...how about giving us all a few number suggestions for the powerball lottery? After we we are all your best friends are we not? You can trust us....really. Randy