Hey John T., kinda long

I'm working on my recently acquired '42 Farmall H that my grandfather bought new. Been in the family ever since. Having charging system troubles. It has been converted from a cut-out on the generator to a voltage regulator mounted under the gas tank, but still 6V, positive ground. Wasn't charging when I got it.
I took the generator & regulator to our local shop. Generator was good, regulator not. Bought new regulator and it did charge, but only 2-3 amps(on a new ammeter) and the ammeter fluttered a lot & constantly, especially at higher RPM's. I tried another regulator, with no success, same problem. I then took both regulators and generator back to the shop. One regulator was good, the other not and generator checked good.
N ow I'm beginning to suspect a back connection somewhere in the old original wiring harness which had been modified when the tractor was converted to a regulator system. So I replaced it all with new wiring. There are no lights hooked up, only the distributor. It is still not charging.
I remembered some of the tests you have posted in the past, so I grounded the field terminal. With the field terminal grounded I get about 7-8 amps and no more fluttering of the ammeter.
What is going on here, did I get two bad regulators or what? Any ideas? This is beginning to make me appreciate my hand start John Deeres with only a magneto to worry about.
Thanks,
Paul

Paul did you polarize the new regulator? http://www.youtube.com/watch?v=PPUfQtVEJGg

Rick

"With the field terminal grounded I get about 7-8 amps and no more fluttering of the ammeter. " Given that statement, "polarization" is fine, so forget that. Be sure you have a good ground between the metal base of regulator and the generator,

At least some regulators are polariy sensitive. Did the "shop" give you a polarity sensitive type and is it for positive ground?

The regulator needs to have a shiny ground to assure it is going to operate the generator correctly. The possible wires going to the electrical box are two. one from the Battery terminal on the reg 10gauge, and one from the L terminal (if it has one on the regulator) that is also 10 gauge and hooked to the light switch fuse holder screw (it supplies all Load power to the lights and the ignition. No other wires should be connected to the light switch, with a regulator. The regulator is connected to the gen Field to Field (14 gauge) and Gen to Arm (10 gauge)
The real test is not to 3 amps, it is voltage at the battery. There needs to be 7 to 7.3 volts when running at 3/4 throttle. The needle will be bouncy and unsteady if it is old or cheap. Needle dampening is a drop of viscous fluid on the pivot, old generator systems are very noisy and have transient voltage and vibrating contacts that are not at all smooth like a solid state alternator.
It is normal to charge 3 or so amps if the battery is charged! Jim
Wiring from Bob M

Paul, if you dead ground the gennys Field post and she charges okay (tels me the genny itself is okay) but NOT when using the VR my first suspect is the VR isnt getting a good ground followed by the VR isnt a proper match for the genny or the VR is just bad.

Run a direct dedicated ground from the grounded battery post to the frame of the VR n see what happens ??????? If still not a good charge then the VR may be misadjusted or not properly matched to the genny or just bad.

HOWEVER if alls well if the battery is charged enough the VR IS SUPPOSED TO BACK OFF TO A LOW CHARGE RATE LIKE A FEW AMPS but after a start up the charge rate is normally high (maybe 10 to 15 amps) for a while at least before backing off to a few amps

The jumpy needed can be bad connections or a bad ground or the genny hasa brush or commutator problem.

Check grounds check wiring and if alls well Id just let it go for a while n see if the VR settles in???

John T

You polarize the generator not the regulator. Not needed in this case as it charges right with the field grounded.

Thanks for all the help guys. When the engine is running at 3/4 throttle I'm still getting only 6.0 volts, so I'm pretty sure that it's not charging. I thought of the regulator ground, so checked it with an ohmmeter and it's good. But it may not be good enough with the currents involved so running a separate ground is a good idea. I will try that next and see what happens. Thanks again,
Paul