Power Factor Correction

• To: tesla-at-pupman-dot-com
• Subject: Power Factor Correction
• From: Terry Fritz <twftesla-at-uswest-dot-net>
• Date: Wed, 28 Jul 1999 17:03:25 -0600
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi All,

	I was playing with computer models all day today and got interested in
power factor correction caps.  I found I can get my coil down to about 8.2
amps RMS input by adding 140uF of capacitance across the neon input.  This
will reduce the VA input from around 1550 to about 1000.  Digi-Key sells
little 20uf AC caps for fairly cheap and using a bunch of these would allow
for easy adjustment of the value.  Reducing the input current would take
the load off the control box parts and let me run the coil and gap motor
off the 15 amp power strip (the strip breaker likes to blow otherwise).  I
did have a few questions for those that know about such things.

I notice that same AC capacitors (like ones from GE) are significantly more
expensive than others.  They are all full-time motor run caps made with
polypropylene (I bet some or oil filled) but I was wondering why the price
difference for what appears to be the same cap?  the 60UuF were $15 for one
manufacturer and $65 for GE...  Digi-Key sells only 20uF but the price is
faily good for the value I need even if I do need to use 7 of them...

Are there any hidden things I should know about like inrush currents, cap
explosions, openload or short problems?  I ran some models with various
faults and all looked very good but...

Is there any easy way to calculate the cap value for a real coil with all
of it's dynamics?  MicroSim could easily find the value but I was wondering
if there was an easy equation or something like that.  The value is not
real critical.

Cheers,

	Terry

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