Oliver polarization

56oliver · Jan 10, 2015

I have a couple questions about the polarization of an Oliver super 77... The tractor is new to me and doesn't charge... All the wire seems good and I know the procedure for polarizing a 6 volt system, all I need to know is, the tractor has a 6 volt posative ground regulator... Is says that on the regulator. The problem is that the battery is hooked up with a negative ground. So should I try to switch the battery to posative ground and then polarize it. Or just leave it like it is? Any input is appreciated... Thanks...

old · Jan 10, 2015

If the V.R. is truly a + ground then likely it bad due to being hooked up backwards at the battery

56oliver · Jan 10, 2015

(quoted from post at 18:26:45 01/10/15) If the V.R. is truly a + ground then likely it bad due to being hooked up backwards at the battery

ok... Is there anyway to test a regulator?

old · Jan 10, 2015

Maybe but if it can be a farmer is not likely to have what it takes to do so

Steve@Advance · Jan 10, 2015

Since it's not working, nothing to loose by trying. Reverse the polarity, polarize it, see if it charges. If not, check the generator, if it checks good, and the wiring is good, must be the regulator.

Remember, the ampmeter will read backward unless someone reversed it.

If it has battery ignition, check the wiring on the coil. It should have the + side to the points, - side to the switch for a positive ground system. Someone may have reversed that also.

fixerupper · Jan 10, 2015

To add to Steve's good advise, if it doesn't charge after you change the polarity, ground the field or F terminal to the frame of the generator with a screwdriver or wire with the engine running at part throttle and see what happens. You might have to scratch around with the screwdriver to get through the paint and rust to get a good ground. If you get a little spark the generator is at least doing something. Have someone watch the ammeter while you ground the F terminal. If the ammeter shows a charge the generator is most likely good and the regulator is not doing its job.

gene bender · Jan 10, 2015

Hook up the batt for pos gnd if thats what the reg says then polarize the gen and you dont polarize the reg. If it doesent charge ground the field if that makes it charge your reg is bad. If grounding the field doesent charge the gen is bad. Just mite be a good idea to take the gen and reg to a repair shop and let them check it out.

John T · Jan 11, 2015

Oliver, here are my responses to a few of your questions.

1) Since the VR is specifically labeled for POSITIVE GROUND I would definitely reverse the battery polarity for POS Ground,,,,,,,,,Re Polarize the Genny (BEFORE starting),,,,,,Then start her up and see what happens.

2) In the event the tractor has had its polarity changed, the ammeter and the coil wires may need changed. If it was factory original POS Ground the Ammeter and Coil may already be wired correct?? So if the ammeter reads back asswards its leads need swapped side to side and likewise the coil should be wired to match battery polarity. If at POS Ground the - gets voltage (via Ignition switch) while the POS wires to the distributor.

3) TESTING of Genny and VR: If you work through my Troubleshooting Procedure linked below, it will tell how to determine if non charging is the fault of the genny or the VR. It shows in Para 5 how to full field and essentially by pass the VR by grounding the gennys FLD post to see if that makes her charge.

John T Long retired Electrical Engineer
John Ts Class A Troubleshooting

Oliver polarization

56oliver

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old

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56oliver

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old

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Steve@Advance

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fixerupper

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gene bender

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John T

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