Bad VR or bad ground?

mkirsch · Jun 13, 2008

Going through John T's generator troubleshooting document.

When I ground the F terminal on the generator, it starts charging like crazy, so the generator is good.

HOWEVER, when I disconnect that ground, the generator continues to charge... I don't think that's covered in John T's document unless I missed it.

The charge current bounces around, so I'm betting on a marginal VR.

John T · Jun 13, 2008

Ya mean I missed something in that long winded procedure LOL??

If the Genny is Okay and the VR working n the battery is good but just low on charge, Id expect the VR to furnish the Field a ground (via the internal VR relay then VR case then gennys case to ground) so she charges just like its posed to

However a jumpy ammeter (I hate when that happens) can be caused by several things:

Poor ground or other wiring,,,,,,burned or carboned VR contacts,,,,,short brushes or a carboned or oily genny commutator,,,,,,,,,weak or stuck brush hold down springs,,,,,,bout a ton of other things lol

Id try n jump a good ground to BOTH the genny n VR,,,,try to clean n degrease the gennys commutator,,,,,,insure brushes arent worn down too low and that the hold down springys are free to keep the brushes down tight,,,,,,,,,remove n clean n wire brush n reatatch charging system wiring

If that dont fix her see what the Bobs or the Jimster have to say?????

John T

Janicholson · Jun 13, 2008

I say if when you ground the F terminal, even when it starts to kinda work on its own, that the VR is not right. If it were mine I would disconnect the battery, the remove the VR cover, and burnish the contacts with 320 , then blow it out and put the cover back on and try it. Covers affect the magnetism, and need to be on. If still wonkee, Replace. JimN

Davset · Jun 14, 2008

Don"t forget the battery post either.
Had trouble with my SA - come to find out it was corrosion on the + terminal. All looked good, but the post was black under the clamp.
Bad grounds are pesty little buggers.

mkirsch · Jun 19, 2008

I picked up a new VR from a vendor on eBay. $25 plus $7 shipping versus $45 + tax from TSC, or dealing with NAPAtards... Figured for that much money, I had nothing to lose. I ordered it Monday night, and it was sitting on my doorstep when I got home yesterday.

After sanding the mounting surface for the VR until it was shiny, I installed the new VR, but it still didn't charge until I manually shorted the F terminal on the gen to ground...

The generator did continue to charge after that, though. Absolutely rock steady, and the needle barely wiggled when I turned on the lights. With the old VR, the needle would go to discharge when I turned on the lights.

Hopefully the system will stay polarized until the next startup...

Bad VR or bad ground?

mkirsch

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John T

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Janicholson

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Davset

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mkirsch

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