Re: Power Factor Correction

to: Terry, et al

Why not just buy them surplus for $2-3 each and save lotsa $$$?


-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Thursday, July 29, 1999 4:25 AM
Subject: Power Factor Correction

>Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>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.
> Terry