Re: Variac faults: what to look for

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dan by way of Terry Fritz <twftesla-at-qwest-dot-net>" <toodamtall1-at-yahoo-dot-com>

Hi Folks,
One variac fault I didn't see mentioned was the brush
travel in the holder. The travel of a brush in a
variac I've recently aquired looked odd to me. I would
turn the knob and the brush would rub along MOST of
the windings and not at each end. I originally thought
the disk that held the brush was bent because the
brush wasn't touching at each end of the spectrum.
Luckily I didn't try TOO hard to bend the disc.  So
then I took the disk off and realized that the brush
wasn't moving in and out of the holder so the spring
could push it down on the windings. Well a half a drop
of marvel mystery oil on the sides of the brush and
WAHLA, now the brush makes contact all along the
windings. The brush needs to move freely in and out of
the holder to make constant contact along the
windings. It was just dry and couldn't move.
Dan--Ft. Lauderdale

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