Re: Variac Troubles -Oops!

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Original poster: "Jason by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jasonp-at-btinternet-dot-com>

Winston,

> More questions...  I didn't clean the area where the brushes slide
> across the windings, so the brushes spark when controlling even a lowly
> 12/60 NST.  Will a simple contact cleaning fix this?  This variac was
> left outside for a LONG time, and had dirt in the windings and all the
> bearings/contacts.  The oxide coat on winding is pretty thick.  What
> have you guys found to reduce brush sparking???  I want to put a few
> taps on this thing, but don't quite know what I'm getting into here.

I would get some fine grade flour paper and clean up the oxide coating on
the windings,  then get a bit of fine oil, and polish them up with the same
bit of (worn) flour paper... Brasso is good too. I use oil to pick up the
dust, and to stop it from building up between the windings. Clean with
meths, and then clean the carbon brush with a bit more flour paper and
meths. When you sand it down, keep it dead flat so ALL the carbon touches
the windings. Be careful with the brush - its probably quite delicate, and
will break easily. AFAIK they are quite hard to find. Make sure that ALL
metal / carbon dust is removed from between the windings - you dont want any
shorts.

Best Regards,

Jason
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