The Stovebolt Site Forums The Shop Area The Electrical Bay Voltage Regulator

Been reading through the forums for months and just couldnt take it any more so I signed up. Hope you can help. 58' Appache with re-built generator and new voltage reguator. Amp meter at full charge at start up and with excelleration. Same simptoms prior to rebuild and new regulator. Battery six months old with cold voltage approx. 12.5. This problem came on all of the sudden. Tinkered with old regulator then noticed bad brushes in generator and hot to the touch. Voltage at bat. posts approximately 16.5 at idle. Wondering about wiring, or any other recommendation. Just so you know, I dont know the difference between a wrench and a pair of pliars.

You have a short to ground either in the generator field circuit or the wiring from the field terminal to the regulator. Disconnect the wire from the "F" terminal of the generator (the small wire), and see if the charge rate goes down. If not, get the generator rebuilt.
Jerry

Thanks Jerry. Gave the battery a charge over nite. Same result. Disconnected the field wire at the generator, same result. The generator was just rebuilt and installed with new regualator yesterday. Symptoms are same as before the rebuild and new regulator. At regular idle showing about 13.75 volts, fast idle 16.5 and up. I've read many of your posts and know you understand this stuff. Thanks.

On the GM generators, the field current is created by residual magnetism in the pole shoes of the field coils, and a small voltage is induced in the armature. The field circuit begins at the insulated brush, and continues through the field coils to the "F" terminal. Try disassembling the generator again and taking the brushes out of it. There should be no continuity from the "F" terminal to the generator housing (checked with an ohmmeter) with the brushes removed. It sounds like you've got a field coil getting grounded to the generator frame that's letting the field current go to ground without being controlled by the regulator. That will put the generator in full output with no way to regulate it.
Jerry

If your generator is putting out high voltage and high amperage with the field wire disconnected from the generator terminal, the field winding is grounded inside the generator. It shouldn't be that way. A couple of possibilites exist: whomever rebuilt the generator connected the field winding incorrectly, or pinched a wire in the end frame, or the insulating bushing at the field terminal on the case is broken or missing and allowing the field terminal to be grounded. Check the terminal to see if it is loose in the housing; if it is, the insulator may be broken- or missing. You can remove the nut and washer from the field terminal and you should see the insulating bushing.

Harvester

I've seen the fiber washer between the field terminal nut and the generator housing get broken or misplaced and cause this problem. The nut grounds the terminal to the housing and puts the generator into uncontrolled output.
Jerry

I agree with the guys it sounds like you have a cracked insulator on the Fld post or field lead or coil grounding to the case of the generator.

Thanks to all of you for pointing me in the right direction. There is a ground at the frame or case of the generator. I'll take the generator back to the shop and as a result of your help, act like I know what I'm talking about. Hopefully, I'll be able to post the resolution by chance this could help someone else. Thanks again.