Repost: NST VA Rating and Power Factor

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

Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>" <vanyo-at-echoes-dot-net>

First, is the reposting of unanswered questions a problem for the list? 
I'm sure this is a simple question for the experts here, but it seems to
have sunk below visibility in the endless flow of posts.

Anyway, again, my main question has to do with the "high power factor"
label, and 495 VA rating on Franceformer 15/60 NST's, as opposed to 900
VA rating on Jefferson 15/60's.  I've depotted a Franceformer in the
past, and it didn't contain a PFC cap (do any NST's?), but I don't
recall if it was labelled the same as these other two are.  

Why such different VA ratings on different 15/60 NST's, and does this
have any bearing on whether anything is to be gained by using PFC caps?

	Thanks again,
	Bill Vanyo

Original post was:

 My power supply consists of three 15/60 NST's.  Two are Franceformers,
 and are marked 495 VA, and also have "High Power Factor" on the label.
 The other is a Magnatek/Jefferson, marked 900 VA.
 
 Does this mean that I will have little to gain by adding PFC caps to
the
 supply?
 
 When adding PFC caps, is there any point in placing them on each NST?
 Since they're in parallel, I can just put the PFC caps in one place,
 hooked in parallel, no?
 
 Also, regarding the problem of tripping the house breaker (It was on a
 15amp breaker, but there is a 20amp available that I'll try next time):
 I've got a 240 volt line in my garage (20 amp breaker).  If I use my
 variac to step this down to 120 volts, will I be able to draw more
 amperage?  The variac is 240 volt 50 amp, and has multiple terminals,
 and I think there's a way to use it as a stepdown (other than just
 leaving the dial at 50%), though I'm not sure how to do this (asking in
 another post).
 
         Thanks,
         Bill Vanyo