Gen won't charge! Starting to lose hair!!!

Got my Farmall A running, Finally! Now I'm having hell trying to get it charging.... I read an old post from John T. Nordhoff that laid out the wiring and test procedures very nicely! I've gone through my hole wiring system and it all seams correct. I tried to full field the gennie to no success, the gennie will motor fine and pick up speed when I remove the ground at the arm post while testing. The symptom that is bugging me is when I start the tractor the amp meter pegs all the way to discharge and batt voltage drops. I've done this with the VR cover removed and the gen coil (the adjustable one) pulls the points together and it discharges. While running I can slip a finger nail under the points to pull it apart and the meter goes to about a 4 amp discharge. During the same time I tried full fielding and the coil just pulls harder.... Not sure where to go next. The VR is an four post; Gen, Batt, L, F and all is wired according to John T. The amp meter shows discharge when the ignition or lights are turned on... What else.. I did polarize the gennie and I've got it set up positive ground.
Any help would be appreciated!

Daniel

dan, i fought a charging problem on my h. everything checked out, genny good vr good, wiring all good. took everything back to the rebuilder to retest, still ok. once installed, no charge. janicholson and john t helped me on it. turns out when the wires were attached to the arm terminal on the genny and tightened, the insulation around the stud was damaged and it kept shorting out. if i remember, an ohmeter on the arm post to the chassis ground with the brushes nsulated (bit of cardboard) showed the fault. a little repairing and it finally charged. dont know if thats your problem, but worth a peek.

Thanks glennster! I'll check that out in the morning!!

I also chased a similar problem around with an F-cub.

The GEN and F terminals had been reversed by the previous owner and the tractor painted with a heavy coat.

The light bulb went on in my head when the electrical shop who tested the generator scratched off some paint around the terminals on the Gen to find the stamped markings.

When they said it checked well within specs and I saw the exposed markings....I knew immediately what was wrong. Ran perfect ever since.

Some Ideas:
Make sure the Smaller terminal is hooked to the Field terminal of the reg.
Make sure the Gen is polarized (while stopped and shut off, jump momentarily between the Bat and Arm terminals of the regulator (it should spark))
Make sure the amp gauge goes toward discharge with the lights on not running. Or less to discharge with the ignition on not running (tests the polarity of the amp gauge.
Try this test: disconnect the generator from the VR. Run a 10 gauge jumper from the (hooked up)Bat terminal of the VR to a place near the GEN Arm terminal (do not connect it, but keep it from touching things it is a hot wire)
Jump a wire from the Field terminal of the gen to good ground.
Start the tractor and run 1/2 throttle.
Now touch the Arm terminal of the gen with the free end of that first jumper to connect it to the system (this eliminates the regulator entirly) Some one should be watching the amp gauge. If it charges, the issue is the regulator. Important!!!! Disconnect the wire from the Arm terminal of the Gen before shutting off the tractor. If it also discharged, there may be a short in the system. Check each wire conductivity end to end. and to ground to assure clear conduction. JimN

Simple test ground the field. If that makes it charge the reg is bad. If grounding the field dont make it charge the gen is bad. Now is everything in the system grounded. Use your OHM meter to check. Lots of problems with the systems in the A is the control case isnt grounded.

Dan, a couple things you say have me a lil worried......

"I tried to full field the gennie to no success"

When you say "full field" what are you doing exactly???? To see if its a genny or a VR problem you DEAD GROUND THE GENNYS FLD POST. If it charges then but NOT otherwise its EITHER a bad or misadjusted VR ORRRRRRR the VR isnt well grounded ORRRRRRRR the wires bad from FLD on VR to gennys FLD post. INSURE BOTH THE GENNY AND VR HAVE GOOD GROUNDS

"the gennie will motor fine and pick up speed when I remove the ground at the arm post while testing"

To do the motor test you first ground the gennys FLD post,,,,,then you apply hot batetry voltage (like from BAT on the VR) to the gennys ARM post n she ought to spin, then you remove the FLD off of ground n it should speed up. If it passes BOTH those tests it ought to charge.

Try the dead ground of the gennys FLD n see if that makes her charge (if so I suspect a VR problem or its not well grounded) ,,,,,,,Insure the VR and Genny BOTH are well grounded,,,,,,

John T

the best solution to solve the one you have now and future ones is to install a 10-si delco alternator i.e. chevorlet alternator a dodge ballast resistor a radio shack diode & 12 volt battery these parts are inexpensive compaired to 6 volt parts if you switch one tractor over you will be satified with the results

don't forget you should have positive to ground, sounds like you have negative to ground, that will make your amp meter read backwards

Definitely not a reversed Amp meter. He says the battery voltage goes DOWN. He also says the meter reads discharge when the lights are on.

The meter should not peg to discharge from just the tractor running.

That tells me one of two things:

1. Generator is reverse polarity and discharging the battery.

2. Dead short somewhere.

It's about a 15 minute job to rig up a temporary wiring harness. All you need is the long wire from the Amp meter to the regulator. Everything else is just short wires from the generator to the regulator.