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Grant Erwin

wrote:

Grant - is the output of the variac connected to anything when its turned on
or is the output open?

Hul

I'll summarize: the variac (with no load) set to 30% output popped the 20A
breaker (Square D QO) in the wall panel. When set to 100%, it didn't pop the
breaker, and once magnetized, I could vary the dial all the way to zero
normally. The variac is in use and appears to control voltage as expected. Many
people have told me that the wall voltage must be wired to the slider, but it
can't be and isn't. My conclusion is that for whatever random reason this variac
has a greater magnetizing current with the slider in a low position than high.
Admittedly, I didn't test this properly. To test it properly I'd use several
circuits, and do a hundred or so tests repeated widely in time to ensure that
the breakers weren't stressed from being recently popped.

Grant