Re: Power Factor Correction weirdness?

• To: tesla-at-pupman-dot-com
• Subject: Re: Power Factor Correction weirdness?
• From: "R.E.Burnett" <R.E.Burnett-at-newcastle.ac.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Wed, 09 Feb 2000 18:45:50 -0700
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Adam,

On Wed, 9 Feb 2000, Tesla List wrote:

> Original Poster: Adam <adamsmith-at-mediaone-dot-net> 
> 
> 
> Can someone explain what I'm seeing when I attempt to power factor correct
> my neons? I've got my DMM in series with the primary of a 12,000 60mA NST,
> and the secondary of the NST is shorted.  With no PFC caps, it reads 7.13
> Amps.  But when I start adding caps in parallel with the NST primary, the
> current reading drops dramatically-- more than I expected it to.  Here are
> the results:
> 
>     PFC Caps    Ammeter Reading (amps)
> 
>     0                7.13
>     50 uF            4.96
>     100 uF           2.81
>     150 uF           1.14
> 
> What's going on here? is this right?

> -Adam

This is normal.  As the output of your NST is shorted,  it is drawing
reactive power only.  As you increase your PFC capacitance, you are
progressively cancelling out the reactive power drawn by the NST.   Around
158uF of PFC should cancel out almost completely !  Bigger PFC capacitors
will then give increasing currents,  indicating that you have gone too
far.

Now you need to connect the NST to your coil,  and repeat the PFC cap
test again.  The optimum PFC capacitor will be different when you have
your TC connected to the NST as a load.  You should not need as much PFC
capacitance to get the minimum current draw,  and this time the current
minimum will not be so low ;-)   Good luck,

							Cheers,

							-Richie,

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