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Re: Power in a TC System
Hi Gavin,
The interactions between the tank capacitor and leakage L of the NST are
quite complex which makes analysis a little tricky. By definition the
P=0.5*BPS*C*V^2 formula is correct for the amount of power passing through
the tank capacitor.
The power drawn from the wall will be slightly higher than this figure
because of I^2R losses and such in the NST and wiring. The supply current
will then be higher again due to poor power factor, so supply current
alone is not a good indicator of real power.
I don't think you can just treat the primary cap as an impedance across
the HV lines, because of the firing of the gap etc. With a static gap
the firing is actually quite chaotic, and power drawn can fluctuate
dramatically.
Hope this helps,
Cheers,
-Richie,
On Mon, 15 May 2000, Tesla List wrote:
> Original Poster: "Gavin Dingley" <gavin.dingley-at-astra.ukf-dot-net>
>
> Hi all,
> Up until now, I have been using the primary tank capacitor reactance to
> judge the power used by my TC system. That is, I calculated the
> capacitors reactance at the mains frequency (50Hz) and divided the
> square of the kV output of my NST by it. P=V^2 / X. Does this give a
> true indication of system power?
>
> The alternative would be to multiply the number of brakes per second in
> the SG by the energy stored in the capacitor, that is,
>
> ((C V^2) / 2) * Bps
>
> Which is correct?
>
> Regards,
>
> Gavin, U.K.
>
>
>
>