Farmall C charging system will not work

This message is a reply to an archived post by John T on June 13, 2008 at 04:26:39.
The original subject was "Re: Farmall C charging system will not work".

Hi I have a 52 farmall super c and I am havering the same problem with the charging system it"s still all original 6 volt pos ground. I have all new wiring, battery, gauges, vr, everything except generator. All tests pass except the motor test on geny when I ground the field the geny is running slow and clockwise if looking from front of tractor, but when I take field wire off ground it starts running counter clockwise at a higher rate of speed. Does that mean something is wrong with geny?

you need to probaply polorize the gen making sure your battery is hooked to positive ground cause your reg is made for pos ground. Thats figuring you have the correct regulator. After all the years hard to tell just what you have by now. But when new the system did have a positive ground system. Do you know what the Delco Remy gen # is on the tag. That would be a good place to start when figuring out your system.

Yes it is a positive ground and my regulator is marked six volt positive ground, not sure the number though! I have been try to determine if geny is bad and a guy by the name John T posted a test by motoring a geny by powering it up itself! I have been polarizing geny! I took geny to get checked out and the kid at the shop tested it and said it was good but not sure I believe him, do to the fact he tested the geny at about 4000 rpm and the tractor is 1815 max rpm! I'm thinking there is a problem with the field Side of geny but not sure what best test is for it!

Something definitely wrong with generator, because you are able to make it run CCW. Very likely the fields. Generally 6v fields run about 2 to 4 Ohms, so you might learn something by measuring that. I say might, because of the wide range & if/where a winding to winding short might be. You could check for field to case shorts by lifting the brush connected to field & armature (remove it or slip a piece of heavy paler between it and armature) and then use Ohmmeter to verify that there is open circuit between case & fields.

What was my guess the last go around I forget lol

Seems to me like there has to be some sort of field windings problem. Im unsure if they are configured (correct ends in and out) and wired incorrect or theres a short to case or just what the heck, but it dont sound right to me and Id be surprised if she works right from what you describe.

To make that electromagnetic field DC Motor/Genny reverse you would have to effectively
reverse the orientation of the fields with respect to the armature (such as swap ends of field windings) which makes me think theres a short somewhere or one of the fields isnt wired using the correct ends, or in bass ackwards or something??? DARN IF I KNOW

They are supposed to (if 2 brush genny) wire with the first fields one end connected to the gennys ARM post,,,,,,,the other end of that first field splices to the end of the field winding on the other side of genny, then its output wires to the gennys FLD post.

The 2 are in series,,,,,,,,,, there can be no shorts to case frame,,,,,,,,,the splice in the middle has to be good and NOT shorted out to case frame.

Things Ive seen go bad are the splice in the middle gets broke or it gets shorted to case,,,,,,,the pass through nut on the FLD terminal gets overtightened and broke open and/or shorted out,,,,,,,one or both the fields becomes an open circuit,,,,,,,,,one or both has a short to case frame.

With the armature removed or the brushes lifted off the commutator (or paper between them and commutator) put one end of an ohm meter on FLD post and other on ARM post, that should read maybe 3 or 4 ohms or so if both field windings are continuous and the splice in middle is good...........Put one lead on case frame AND THERES SHOULD BE NO CONTINUITY to case frmae or else theres a short.

Thats about all the guesses I can come up with sittin here. I just cant remember ever having one do that on a bench test, it should spin smooth n even with FLD grounded (Armature and brushes n bushings likely okay) but then speed up if FLD ungrounded (fields liklely okay) if not she shouldnt charge????????? if so she should

Hope the other sparkies weigh in here cuz Im outa smarts n ideas but never too old to learn

John T

Try motorizing with a 12 volt battery, positive ground. If it still reverses, you have a generator problem, which I think you have.

Due to the difference in pulley size between the crankshaft and the generator, 4000 rpm in not out of range for the generator speed.

Just wanted to let everyone know that got a new/used geny and bench tested it, switch it out and worked perfect so charging system is fix! Thank u all for ur reply"s and input! Amazing how the simplest test are sometimes the best!