Re: PFC Question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Esondrmn@xxxxxxx 

In a message dated 11/2/2005 4:22:34 PM Pacific Standard Time, 
tesla@xxxxxxxxxx writes:

Hi Ed,

I must not have explained myself properly.
My PFC caps were directly across the out-
put terminals of the variac and consequently
across the input terminals to the transformer.
That's in parallel with the input terminnals of
the transformer, isn't it? And the variac would
start the resonant saturation hum even with the trans-
former disconnected from it, or with no load.
I even tried removing one of the 100 uFd
caps to make it 600 uFd PFC but that didn't
really seem to help so at that point, I just decided
remove them altogether.

David Rieben

David,

It does sound like a 60 Hz resonant problem - between the caps and 
the variac I guess.  These are AC line caps, like motor run caps, 
yes?  Not sure what to tell you.  I use a 5kva pole transformer and 
don't use pfc caps.  It wouldn't be a bad idea however since I do pop 
the breaker some times.  Does anyone know or venture to guess how far 
off the power factor is on this kind of set up.  The transformer is 
primarily an inductive load, but does some of that get canceled by 
the capacitive load from the primary cap?

Ed Sonderman