12 volt positive ground on oc3

[Greg-in-WV]

I just inherted this OC 3 from my grandfather. It sat for a few years, then everyone that seen it thought that they could get it running. Ive been reading the repair manual for it and it says that it is a positive ground. Its was run for years, in the standard negative ground. What might this hurt , other than the generator.

[ggibby]

The tractor may have already been converted to negative ground.
This I beleive can be done by repolarising the generator, along with some rewiring and a 12 volt cut out to keep from over charging the battery.
If an altenator has been installed already then most of them are negative ground.
The whole thing can be put back, study your manual, there is a wiring digram in there that can help.
Good Luck,
Regards,
George Gibby:)

[Blake Malkamaki]

Greg, does your switched lead to your coil go to the positive or negative terminal? Does it have a balast resister in the line going to the coil? Alternator or generator?

What part of West Virginia are you in? I had a girlfriend down there for a couple years.

Blake

[Greg-in-WV]

There is one wire that goes from the battery to the start switch to a single pole on the starter case. Then one wire from one of the starter mounting bolts to the battery. Two wires from the gen to some kind of regulator then one wire back to the battery. almost like the book shows. I tried to test the output of the gen to check to see if its pos or neg, but the diodes must be gone or bypassed becuse it put out ac current.


blake I live in the eastern panhandle, between maryland and virginia, not to far from pennsylvania

[Blake Malkamaki]

Diodes? Does it have a generater or an alternator?

[Greg-in-WV]

generater - I said that becuse Iam not quite sure how a generater would keep from producing AC voltage

[thecatskinner]

I don't want to confuse the works here, but if you have reverse polarity it is necessary to polarize both the generator and the regulator.  
It is quiet possible that the regulator is already fried.
Rather than try to go through the details of polarization here--and it varies depending on the type of system you have, do a search using your system (as in Delco) and you will come up with detailed directions on the procedure.

I am still a bit confused about your meter readings.  Did you have the meter set for DC?  Did you get a reading off the Field Terminal?

If you can't find the procedure post the make of the generator and I will try to help you out.

[Greg-in-WV]

I tested the field terminal with my fluke meter set on the scope side that auto-ranges, and the generator  would put out 4.5 to 9.5 volt A/C ( it jumped around so much it was hard to tell) . So I took the generator and the voltage regulator to my look starter and alternater rebuilder. They say it looked like some one tried to rebuild it to 12 volts but it was a poor job. Now I have a rebuilt generator and voltage regulator that is set up for 12 volt negative ground. It only cost me $150. With 1 year warranty. So now all I have to do is get it timed right and I'll be ready to put this thing to work.

Hope to post some pics soon!!

[John Schwiebert]

The trick is still to polarize it. Do you know the make and model of the generator. There  are "A" circuit generators and "B" circuit generators. They do not polarize alike. Call the supplier if they did not give you instructions before you fry something.

[John Schwiebert]

Generators produce D. C> current, your meter should be on the D. C. scale.