> A quick&dirty test of the insulation might be to simply connect the
> (fused) unloaded xfmr's primary to 220 briefly to see if it can stand
> twice the voltage it will see when you actually use it. Then lift the
> secondary winding from ground, ground the other end and re-test to
> verify the insulation at both ends.
Woah there! Don't do that!
Most efficient transformers are designed to run with the core near
saturation. Very few would have safety factor of 2x.
Primary current will go sky-high if the core saturates, and that is
very likely to happen in most designs. You would have the
saturated voltage across the primary bucking the line, and the rest
of the voltage would be effectively applied across the wire
resistance of primary as if it had NO core at all!!!!
You not only wouldn't have a good dielectric test because
secondary voltage would be limited by core saturation...the
transformer (or switch, plug, circuit breaker, etc) might blow up
from the primary current!
73, Tom W8JI
W8JI@contesting.com
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|