Sparks if the generator is hooked up!?

:?: Here is a terrible drawing of the wiring diagram:
http://img828.imageshack.us/img828/1632/14300806.png

This is an Allis WD45 that was converted to 12v negative ground by a previous owner. It then sat in their barn for 15+ years and mice ate the wiring. I bought it for scrap price, rewired it with a simple battery to coil to distributor circuit, changed the fluids and had it running in a couple of hours.

I've done the sheetmetal, body work, fluids, gaskets and paint. At this point. She's gorgeous. Now its time for a real wiring job. If I remove the generator from the circuit, the tractor starts and runs great, all the lights and the implement accessory light work, its just perfect!

The wiring on the generator and vreg were thankfully not eaten by mice, but I'm having trouble figuring out the circuit. There are no labels on the generator or vreg except for a single A stamped in the post coming out of the top of the generator.

As soon as I run a 10ga wire from what I believe is BAT to the discharge side of the amp gauge (the green wire), the wire starts spraying sparks, the amp gauge goes full discharge and I can't start the tractor.

With the green wire disconnected and the tractor running, I get about half a volt out of what I think is the BAT terminal to the negative battery post. From the positive post, I get -12.8 volts.

With my ohmmeter, I show continuity between all 3 terminals on the vreg, and both terminals on the generator to the negative post on the battery. I believe the entire generator circuit is somehow shorted to ground, and the reason for all the sparks is that the power is taking the easy route out across the amp gauge and going to ground at the generator.

Now that I've said all that, where do I start? I don't know if its just a polarity issue with the generator, if the generator/vreg armature is stuck, if the wiring is all messed up, or if the vreg is bad?

I'm about to give up, park it, toss a tarp over it, rip the generator out and drag it to a local Allis dealer...but I'd like to at least have a clue what to tell the poor guy at the service desk. And I'd also like to know what to expect on the repairs front. I don't need someone charging me to transfigure my whooptie-jigger if I just need a new vreg, or to jump a couple points on the terminals.

Anyone able to help out a nooby trying to rescue some old iron?

Edit:sorry about the lack of a hyperlink for the wiring disgram, it says my account is too new to post images or links.

You should post this on the AC forum too as you will get more responses. Hal
PS: That image url for you wiring won't post.

One thing I see on you drawing , is you have a negitive ground, which is backwards. Should be positive ground on the battery when you have a generator.

First question, is this certain to be a 12 volt conversion, or did someone in the past just put a 12 volt battery in it? If converted the coil should either indicate "12 volt, no resistor required" on the coil, or have a big resistor between coil and ignition switch. Voltage regulator should also be labeled for 12 volt. Lights should be 12 volt.

Your diagram shows a generator with 4 terminal regulator. If you remove the screws and wire clamps from each terminal, the terminals should be stamped F B L and A. The A (armature) is usually by itself and goes to A on generator. F (field) on regulator goes to F on generator. B (Battery)on regulator goes to Ammeter and L (Load)feeds the ignition and light switches.

Your description about 10ga. wire indicates that the cut out contacts in the voltage regulator are stuck closed, allowing battery to rapidly discharge through the generator. If so your options are to replace the regulator or do an alternator converstion.

A generator system can be configured to work with either positive or negative ground. The voltage regulator should be labeled "positive ground only", "negative ground only" or " positive or negative ground".

With negative ground the coil "-" terminal connects to distributor. With positve ground coil "+" terminal connects to distributor.

Connect ammeter to show negative with lights and/or ignition on, engine not running.

If you choose to replace the regulator it would be wise to polarize the generator. With battery connected and engine not running, monentarily jumper from Arm to Bat on regulator or any convenient equivalent connection.

Thanks rvirgil, thats an extremely helpful post. I had assumed the issue was with the vreg, but didn't know where to start.

To answer your questions, the coil was stamped 12v no resistor required. The bulbs were all 12v (and they still work), and the coil was wired correctly. It was a 12v battery and none of the bulbs were blown it also came with a spare generator that I was told was the old 6v one. I'd guess it was converted...unfortunately, the previous owner passed away. I purchased it from his estate sale and only had the word of his stepson to go off of.

I'll pop the top on the vreg to look around for markings again. It should be a bit easier now that I know what I'm looking for.

Thanks again everyone!

OOPS. Forgot he said converted to 12 volt.

(quoted from post at 19:37:15 09/20/10) OOPS. Forgot he said converted to 12 volt.

Click to expand...

hat's OK. Not a problem. Can be made to work either way.

I took alot of sandpaper to the regulator terminals and managed to find all the markings that had been painted over.

Thankfully, I can confirm that it was wired up right, so it sounds like those points are closed up as you described. Time to go shopping!

Thanks guys,
Ryan