Re: Powerstat Type 10B Repair Help

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: FIFTYGUY@xxxxxxx 

In a message dated 4/24/06 3:36:54 PM Eastern Daylight Time, 
tesla@xxxxxxxxxx writes:

>Can I just whittle a new one from say a D-cell center
>carbon, or would that be too resistive? Any better suggestions before
>I go ahead and burn the house down?

    I can't say anything about D-cell electrodes, but I had a 
similar problem with a 20A variac.
    I repaired my wiper by grinding a DC motor brush down to fit the 
holder, and soldering it in place. Yes, I know solder deosn't stick 
to carbon, but it worked well enough to secure it. Apparently the 
factory brush was plated on one side, and this is what the factory 
solder bonded to the holder. Functioned fine when tested.
    If you want to try this kind of repair and need a brush, bop on 
down to your local motor repair shop and buy a cheap little brush 
that they've had sitting around gathering dust. Most shops accumulate 
spare oddball brushes, and they can be pretty cheap - especially used 
ones. Or you can buy new ones from McMaster (small selection). Plus, 
a motor brush often has a wire braid pigtail you can bring out to the 
wiper to assure a good electrical connection.
    You can often get repair parts for variacs, but I think the 
replacement wiper for mine would have been something like $50!

-Phil LaBudde