Another generator question

Just got a D17 Series II. It was connected - ground when I got it. The lights didn't work and the battery wouldn't charge. I switch that around so now I have lights but the battery still isn't charging. I polarized the generator before starting it but I'm wondering if the damage was already done before I got it. One point in the voltage regulator was stuck and looked burnt. Also, I checked voltage across generator posts with the tractor running(F & A) and it shows no reading. Should there be voltage on the generator even if the voltage regulator is shot? I did notice one of the post on the generator is loose. The ammeter goes way negative when the lights are on. Do I have to go to an AGCO dealer for a voltage regulator?Can the generator be repaired? Hopefully I can get this resolved before it starts snowing! Thanks

If the battery was hooked up backwards. The reg is shot.

You can buy regulators almost any where. Auto parts stores, on line like steiners, nnalert, and yesterdays tractor company.

The loose terminal on the generator will need to be fixed.

Have you tried grounding the "F" terminal with the tractor is running? it should charge at least 14 volts

Thanks for the info. I was just looking at it a little close and it appears the springs on the brushes are broke so I'm going to have to pull the generator off for sure.

check in your area for a starter/generator repair shop and take both the genny and the regulator to them. They will check it all out and make repairs as necessary. LOL Bob

"I polarized the generator before starting it but I'm wondering if the damage was already done before I got it."

If at any time the Genny was polarized opposite from the tractors, the Voltage Regulator may have been damaged (such as burned stuck contacts etc)


"One point in the voltage regulator was stuck and looked burnt"

Such may have been caused by what I first mentioned


"Also, I checked voltage across generator posts with the tractor running(F & A) and it shows no reading."

The Output of a generator is produces between case/frame ground and the Armature post, NOT across ARM to FLD.

"Should there be voltage on the generator even if the voltage regulator is shot?"

If the genny is good, it can work and produce even without a Voltage Regulator in the circuit provided the FLD has a ground return path. SEE PARA. 5 IN MY TROUBLESHOOTING PROCEDURE TO SEE IF A GENNY IS GOOD WITH NO VR IN THE CIRCUIT

If you work through my Troubleshooting Procedure it can answer many of your questions and help find the cause of non charging.

John T
John Ts Charging Troubleshooting

I didn't look over John T's guide but if you ground the generator field terminal (to the battery ground) and that makes it charge then the regulator is either shot, or not grounded, or incorrectly adjusted. The loose post came from somebody cranking on the outer nut without holding the one under the terminal with a thin wrench. It could be OK or could be trouble, depends on how many rotations the wrench 'tard took it before stopping to wonder what was going on. It is possible to convert a tractor to negative ground as some have been however some have been half converted by people who should not be fooling with such. You need to figure out what is going on prior to installing a new regulator. Two things to check to see if it has been switched (by somebody who knew what they were doing) First thing is the ignition coil, negative ground should have the (-) primary terminal going to the distributer Positive ground should have (+) going to dis. Another thing to check is turn the lights on with engine off and look at the amp gauge. Should of course show discharge, If it shows charge then (at least part of) the tractor has been converted to negative ground.

Once I find that something has been fooled with I trust nothing and go through everything. Sure beats many trips to town to replace burned up parts and scratching head.