Re: A few quick questions....

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<FutureT-at-aol-dot-com>
> 
> Alan,
> 
> Yes, an NST can draw more than its rated power especially if you
> power it with a step up variac (260V).  With an LTR cap, and step
> up type variac, a power factor corrected NST can draw double the
> rated power or more.  A resonant sized cap will also increase the
> power draw when using a step up type variac.  If you don't use
> PFC, then it will draw an even higher current.  (it can be surprisingly
> high in fact.)

	With a so-called "matched capacitor" the secondary is in series
resonance, and if there were no transformer saturation the current could
be several times the rated current.  With no other loading the
transformer can and will destroy itself.  I think this is the cause of
many of the failures reported here - safety gap non existent or set too
wide.

	As for the power factor correction, once you hang a capacitor on the
secondary different rules apply and the capacitor may or may not help
any.  The PFC capacitor is intended to supply the reactive current at
the normal operating load (full load? never have seen it stated), not
for the input current with capacitive loading.

Ed