Re: PFCs

In a message dated 99-10-22 08:29:38 EDT, you write:

> Hello All,
> Would a bank of paralleled motor-start caps be suitable as a power factor
> correction cap? I I calculated, if memory serves, something like 80uF or
> 90uF for my 12kV 60mA NST. When powering my TC, it blows a 10 amp fuse no
> problem...   ...and I really wish it wouldn't. Since then I could safely
> fuse my variac with the fuse holder built into it.
> Grayson Dietrich >>


I must admit that I do use motor-start caps for pfc of my NST's, but it's
not recommended.  Those units are not for continuous running, so they
tend to get warm and I'm told they can explode.  Another thing to 
consider; depending on your tank capacitor size, a 12kV, 60ma NST
may draw considerably more than it's rated current, especially if you
crank up the variac output voltage above 120 volts.  [My 12kV, 30ma
NST draws 620 watts (instead of the rated 360 watts), even when 
using pfc, when the coil is operating.]

The caps in oval or square metal cans are the prefered pfc types, some
cylindrical ones may be OK too.  There's usually a range of values that
are acceptable, for example if the NST calls for a 50uF, you may get similar
results using a 25uF. 

John Freau