RE: Variac fix
>From your photos, it appears that your variac does not have the fixed taps a
few dozen turns from the end of the winding that allows it to output up to
120% of the input voltage. If this is the case, then the loose wire that
you show needs to be connected to the "hot" side of the input power. It
sounds like this end of the winding was toasted, you may need to unwind a
few turns and this wouldn't be a problem, except that you'll need to find a
way to ensure that the brush doesn't slide off the end of the windings if
rotated too far. Remove enough to ensure that burnt-bare wire doesn't short
to the core and that adjacent turns don't short.
Most variacs have some type of goop, usually black, applied to some area of
the windings other than the brush-surface, to keep the windings from
shifting. It's possible that some of the black stuff you see is this goop,
possibly melted. You may need to anchor the windings with some epoxy, and
sand or file the brush-surface so that the brush slides smoothly over it.
You didn't mention the condition of the brush assembly. Did the brush ride
smoothly over the good portion of the windings?
Waltham, MA USA
>Original Poster: "Alan Yang" <ayang01-at-earthlink-dot-net>
> I bought a Suprior Electric Powerstat Variac rated -at- 16.7 amps a few
>back. Tonight I finally got around to looking at it. Taking Ross'
>suggestion, i opened up the variac and cleaned it out. I carefully removed
>all parts and cleaned the housing first.(I was being lazy and didn't want
>deal w/ the actual variac yet) When i finally got to teh wire coil, i
>noticed that in the inside, part of the wire was black, and that it was
>broken. Further moving of the wire caused it to fall right off. Now i have
>wire sticking out of this variac. A picture of this is at
> After i moved this wire a little, some black stuff started to
>the coil and i'm not sure if this is normal. A picture of this black stuff
>is at http://members.xoom-dot-com/hvfreak/variac1.JPG
> I'm presuming that this broken wire is bad and the black stuff is
>because this wire was burned out? How can i fix this?
> Thanks ahead for any imput on how to fix it.