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Re: Variac brushes (fwd)

Original poster: Shaun Epp <scepp@xxxxxxx>

I've replaced those brushes too, using the same method. I also gently hammered the brush holder to snuggly hold the brush in place. This might help. Of course if you hammer to hard, you'll crush the new brush. You can spread the holder out abit by putting the shaft of a phillips screwdriver across it and gently hammer.

Good luck, it's fiddly work.

Shaun Epp

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx> To: <tesla@xxxxxxxxxx> Sent: Sunday, January 30, 2005 12:02 AM Subject: Re: Variac brushes (fwd)

Original poster: "david baehr" <dfb25@xxxxxxxxxxx>

The brushes in this variac seemed to be a press fit, one I pushed out of its holder with just my finger nail , the other (it has two ) was a little harder and had to be broken out. I did pick up a couple of used brushes from a motor shop, and made a couple of attemps , tryin to make them snug, but not to snug in the holder, but each time they would crack. I'll pick up a couple more and give it another shot. $60 + is alot for a brush replacement, but, it may come to that. Thanks!! ,dave

>From: "Tesla list" <tesla@xxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Re: Variac brushes (fwd)
>Date: Sat, 29 Jan 2005 21:18:16 -0700
>Original poster: FIFTYGUY@xxxxxxx
>In a message dated 1/29/05 4:18:11 PM Eastern Standard Time,
>tesla@xxxxxxxxxx writes:
> > > Do you know where to buy brushes for an Ol General Radio
>variac, or ,
> > > how too repair them ??
>     Well, I had a Superior Electric variac that needed a repair of
>the brush assy. One of the surplus 240V/30A units had been trounced
>during shipping, and the brush and wiper were shattered.
>     Since I have access to a bunch of carbon motor brushes, I took
>a spare and ground it down to the size of the original variac brush.
>I wasn't particularly concerned with the grade of the original or
>replacement. So far, so good.
>     What I did discover was that the original brush had a metal
>foil somehow bonded to the sides that didn't contact the windings.
>These in turn were what were soldered to the brush holder to keep
>the brush in place.
>     Since I didn't have any brushes with anything similar, I
>mounted the sized piece of carbon into the holder with a bed of
>solder I carefully melted with a torch. It seems to have set up
>quite nicely.
>     FWIW, replacement brushes are available from the current
>manufacturers of variable transformers (Staco, Superior, and the
>folks who took over the Westinghouse(?) ones). Might be easily
>modified for your Variac.
>-Phil LaBudde