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Re: variac
Subject:
Re: variac
Date:
Wed, 19 Mar 1997 00:30:32 -0500 (EST)
From:
FutureT-at-aol-dot-com
To:
tesla-at-pupman-dot-com
>Still, I'm curious as to what percent I may be able to overdrive a
> variac. Maybe this is too general of a question as it probably depends on
> the make of the variac and other factors.
> Thanks for the help!
> -Bert S.
>>
Bert,
One time I drew 40 amps through a 10 amp variac -- blasted copper right
out
of the winding, so 4 X seems to be too much! But I often draw 100 amps
through a 44 amp variac for a few seconds, but I don't really recommend
it,
although the brochures imply that it's acceptable. Variacs are pretty
tough
beasties, but overcurrents can cause plenty of damage. The free little
booklets are available at electrical supply stores, and give all the
variac
specs, and tell how much you can safely over-load them and for how long.
They seem to handle double their ratings reasonably well for short
durations. It's a matter of heat, and brush roasting. It all depends
on how
much you're willing to push them, and whether or not you have a
replacement
supply of cheap ones to toss in place after you toast the originals. I
like
to use the correct rated variac in most cases. Sometimes I run 50%
over.
Hope this is helpful.
Towards optimal coiling,
John Freau