Re: PFC caps

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Robert,

I am holding a Panasonic 20uF 180VAC true continuous AC cap.  It is about
1.5 x 1.5 x 0.75 inches...  Your caps seem far too small to me.  If they
have polarity makings on them like a DC electrolytic, then something is
really wrong.  I think you have DC "buss caps" there and not true high
current AC caps.  In that case, if you hook them across the AC line they
will explode in a pretty flash ;-))

You want "motor run" caps that are either dry polypropylene or oil filled
caps.  It is rare to find them over 100uF in value.

If you put a 100uF cap across the 120VAC line voltage, the current will be
a continuous 4.5 amps.  So the cap needs to run 4.5 amps of current all day
long.  That takes a special cap with a ton of safety ratings.  Not a
"typical" cap at all.

Cheers,

	Terry


At 10:08 PM 7/27/2001 -0500, you wrote:
>I recently dismantled an old computer to get some parts out of and i
>salvaged a couple of 200v 500uf capacitors out of the power supply. they
>seem awful small though (about 1 inch tall, 0.5 inch diameter). If I
>string them together in series I should have just the right amount of
>pfc for my bank of 5-9/30's. could I use these or do I have to have a
>pfc for each individual NST? thanks a lot,
>Robert
>