Testing a VR

[Farmall 504]

Have a neighbor that has a really nice original Farmall 140 HC his dad bought new and claims to keep having bad voltage regulators. I ordered a new one for him, the one we're replacing looks brand new too, and put it on for him, he's an older fellow now, and he's getting a new battery to put in now. How should that unit meter out? The fact that he keeps having problems makes me think something else is causing it. He did have a weak battery on it, but says this is a long term problem. It's funny, he says all VR's have always been that way, and told me of the experiences he's had. I've not had many problems with them over the years in cars and tractors, other than old ones going bad. Really old ones. I imagine mine is at east 15 years old, likely older as it was on it when I bought 15 years ago.

Suggestions and advice appreciated.

B

 

[gene bender]

where did you get the regulator is it for the gen that is on the tractor

 

[Janicholson]

If you have an amp meter DC 10 or 20 amp ability, use it in the field circuit. it should be about 2.5 to 4 amps maximum. more than this indicates that the field is drawing more current than it should. If reliability is desire, purchase a Delco 10si alternator. They can be made to align easily. If it is 12v this will work, if 6v the bulbs and ballast resistor are needed in the ignition circuit. the coil needs to be hooked up so the _ terminal goes to the distributor. The battery needs to be negative ground. Jim

 

[Steve@Advance]

Yours is a common story.

The new regulators are generic fit all's. Back when they were in demand, each regulator was closely matched to the generator it was connected to. They were assigned a polarity by the alloy used on the contacts. None of that happens now, they are imported dinosaurs that generate little profit for the manufacturers.

But a couple things you can do:

Before the next regulator is installed, and after the battery is replaced, just to say you did it, polarize the generator. Be sure once the battery is installed it always gets reconnected the same polarity, and gets charged the correct polarity.

Assuming this is a Delco generator, to polarize it, run a jumper from the non-grounded battery post and spark it to the A terminal pf the generator. Only touch it long enough to observe a spark, don't leave it. Do this before the engine is started.

When installing the regulator be sure the base is grounded. Some have rubber straps or grommets, those need a ground wire. However it is grounded be sure it is cleaned down to bare metal so no doubt that it is grounded.

Check the wiring. Be sure there are no crumbling, pinched, burned, chewed wires touching each other or going to ground. Look for loose connections, especially on the back of the amp meter if equipped.

Choose your regulator. There are companies that supposedly offer higher quality regulators. I have no experience with them, but look around the net and choose carefully. There may be something to it, or complete fake, do some research first.

But I think Jim is probably on the right track. Check the field current amp draw. To have gone through that many regulators is leaning to a problem with the generator. Shorted field windings is not a real common problem, but it happens. Trouble is doing something about it. So many "rebuilders" are not up on generators. They don't see them much anymore and the old timers that knew them well are about all gone now. Unless there is a reputable shop near by that will listen to your story and stand behind their work chances are you might get your old problem back less a pocket full of money!

Unless the owner is trying to keep the tractor show quality original, I would lean toward converting it to an alternator. There are lots of choices. The Delco 10SI is the most common, cheap and readily available. They can be bought for 6v positive ground, they can even be disguised inside a generator case. Might be a solution you could discuss with him.