"Jim Wilkins" wrote in message
news
"DoN. Nichols" wrote in message
...
On 2017-06-10, Jim Wilkins wrote:
"DoN. Nichols" wrote in message
...
On 2017-06-09, Jim Wilkins wrote:
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This addresses the limits to brush current, my concern when using
them for bench testing:
http://variac.com/ShortTermOverload.pdf

Specifically I was confirming the loosely specified time-current curve
of the breaker intended to protect the Variac brush, using the
short-circuit-tolerant arc welder transformer to boost the current so
that 15A from the Variac put 50A through the breaker. The transformer
has enough self-inductance that it needed a good fraction of line
voltage to reach 50A on the shorted output.
-jsw