"Grant Erwin" wrote in message
...
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

Grant,
I dont think you have ever clearly stated:- does this failure occur with
no NO connection to the slider or do you have some load connected.

Also there are variacs around built for 400hz and aicraft use.

It would be great if you could take a photo of the whole thing and also
the name plate so we could understand what we are arguing about.


John G.