Tractor Generator Problems

RCP

Well-known Member
Location
Grove City Pa
The tractor is an Oliver 660 that is 12-volt negative ground with a generator and a regulator.

A week ago, I ran the tractor, and everything seemed to be working fine, the amp gauge showed about 10 amps of charge. I tried to start the tractor today and the battery was completely dead. I think I may have left the key in the accessory position, but I am not positive. I charged the battery for about 2 hours and the tractor started quickly. The amp gauge did not show any charge, so I started looking for issues. I found that a wire from the regulator to the generator had burnt in half. I replaced the wire with an inline fuse (see pictures) and as soon as I touched the post on the generator the 20 amp fuse blew. I pulled the cover from the regulator and found that the points on the right side were welded. (see pictures). I cleaned both sets of points with 600 grit emery, replaced the fuse and started the tractor but amp gauge was on zero.

What testing should I perform?

Would it help if I polarized the regulator, and if yes, how is that done?

Is the regulator shot?

Is the generator shot?

I was hoping to keep the charging system original, but if regulator or generator are likely bad, I have a mini Denzo alternator I can install.

Thanks
Rich
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The tractor is an Oliver 660 that is 12-volt negative ground with a generator and a regulator.

A week ago, I ran the tractor, and everything seemed to be working fine, the amp gauge showed about 10 amps of charge. I tried to start the tractor today and the battery was completely dead. I think I may have left the key in the accessory position, but I am not positive. I charged the battery for about 2 hours and the tractor started quickly. The amp gauge did not show any charge, so I started looking for issues. I found that a wire from the regulator to the generator had burnt in half. I replaced the wire with an inline fuse (see pictures) and as soon as I touched the post on the generator the 20 amp fuse blew. I pulled the cover from the regulator and found that the points on the right side were welded. (see pictures). I cleaned both sets of points with 600 grit emery, replaced the fuse and started the tractor but amp gauge was on zero.

What testing should I perform?

Would it help if I polarized the regulator, and if yes, how is that done?

Is the regulator shot?

Is the generator shot?

I was hoping to keep the charging system original, but if regulator or generator are likely bad, I have a mini Denzo alternator I can install.

Thanks
Rich
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The side with the normally open points is the cut out side. These points close when the generator puts out enough energy to pull them closed, then charging commences. The normally closed points are the regulator side. You can't really see it, but they vibrate enough to regulate the field. If you put pressure on the spring end with your finger while charging you can watch amperage, and voltage rise.
I wouldn't trust the regulator now. You can probably look in the open end of the generator and see if it's toasted. It is possible to check the generators' charging ability without the regulator, but I'm not going to try to explain that. Maybe someone else will.
A friend shut off his AC D15II, not realizing the cut out side of the regulator had apparently stuck closed. His generator, regulator, and heavy wire to the ammeter all fried. It's a wonder he didn't lose his tractor. That's a problem with older tractors with no fuse protection. Now whenever I shut off a tractor with a generator I watch the ammeter to make sure the cut out opens, and the ammeter goes to zero.
 
You need to take the generator and the regulator to your favorite and competent auto electrical guy for a thorough diagnosis. It is far easier for that guy to diagnose the short issue with his test equipment which may be draining your battery and blowing the fuse. Could be the regulator or the generator. What you can do is to load test the battery. If the battery will not hold a load test for a minute or two at 10-11 volts, the battery may be faulty and overload the charging system which may compromise the generator/regulator. The whole system, battery to generator, works just fine if everything is in sync.
 
To test the generator there are two considerations: the cutout pull in windings may be fried. They are inside the heavy wires, and cause the initial closing of the cutout. it is held in position by it and current in the big wires wrapped around the pull in wires. The second is that the cutout may be unable to close from the abuse the contacts have endured.
To test the generator, remove the belt and disconnect both wires. Use a jumper wire of 10Gauge to go from the battery to the Arm terminal of the generator. The generator should spin like a motor (30 second test duration). That would be good!!! The next test checks the field windings. Get a second jumper (12 gauge is good) and ground one end to bright and shiny grounded metal. Start the first test again and with the generator spinning well, touch the ground test wire to the F terminal of the generator. If the field is OK, the motoring generator will slow down substantially, but not stop. If it passes both tests, the Gen is probably good. Get a new (quality) regulator. No need tho polarize any regulator, and you just did polarize the generator. Jim
 
I appreciate the information and guidance, I do not know of anyone who works on generators or regulators in my area, and my track record with generators is not good. I will put the Denso on the tractor and keep the generator and other parts in case I decide someday to put it back to stock.
 
Follow up 2

I installed the Desno Alternator and to my surprise the amp meter showed negative with the engine running and the alternator supplying 14.5 volts. So, I shut off the tractor and turned the key to run position and it showed positive. It appears that the amp meter is wired backwards, and I suspect the generator never was charging the battery. Since then, I have reversed the wires on the amp meter, and everything seems to be working the way it should. I am still confused about why the battery was dead and why the wire on the regulator was burnt off.
 
You said the shop said that both the Gen and regulator were DOA.

If the regulator had a short that could be the reason.
Another reason could be the cutout points stuck closed and discharged the battery through the regulator into the generator and the wire between the regulator and generator was the weak link (things like being partly broken and bad connections could lead to overheating).
 
A friend shut off his AC D15II, not realizing the cut out side of the regulator had apparently stuck closed. His generator, regulator, and heavy wire to the ammeter all fried. It's a wonder he didn't lose his tractor. That's a problem with older tractors with no fuse protection. Now whenever I shut off a tractor with a generator I watch the ammeter to make sure the cut out opens, and the ammeter goes to zero.
Same thing happened on my JD 730... melted all the insulation off the wires from gen to ammeter (burnt the gauge up too) from ammeter to starter, and even the big cable from battery to starter.
It was replaced with an alternator instead of repairing the gen and regulator.
 

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