From: John De Armond
Subject: Re: Onan gen run problem
Date: Wed, 15 Sep 2004 16:46:28 -0400
On 15 Sep 2004 17:09:29 GMT, "topkart"
>Have a Onan problem and hoping the experts here can help me out.
>My gut is telling me its probably the slip rings, so I am asking how to
>check and clean them or what elce to check, I do have a digital VOM just
>no service manual.
>Thanks much for any input.
That's probably the best request for help I've seen in this group!
Anyway, my gut is with yours. The advice from Evad to check for crud in the
brush holders is good but I don't think that will be the root cause here,
since you can bring back the output by running the thing for awhile.
The best thing to use on the slip rings is a glaze breaker stick. This is a
rubberized abrasive stick made for the purpose of breaking the glaze on
commutators and slip rings. Any electric motor repair shop will have them.
If you take your rig by a shop and already have the inspection cover off, they
might break the glaze for free. Otherwise just buy a stick. The stick is
simply held against the running slip ring until the surface is bright and
A distant second best solution is to use very fine, say, 400 to 600 grit
non-conductive sandpaper. Don't use aluminum oxide or carborundum, as they
are conductive. Garnet is fine. The major problem with this solution is that
you have to stick your fingers in and amongst electrically hot things to get
to the slip rings. Unplugging the voltage regulator so there is little output
makes it safer but the residual magnetism will still generate some voltage.
I'd go to the trouble of finding a motor shop and getting a glaze breaker
stick if it were me.