# Re: Peak Primary Current

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• Subject: Re: Peak Primary Current
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• Date: Wed, 20 Apr 2005 13:29:12 -0600
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Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>

This is the peak current on the first half cycle.  If the pulse were a nice
rectangular envelope (which it is not), you'd still have to divide by 1.414
to get the rms current, which is what you should be using for power
dissipation calculations. There are handbook tables for damped sinusoid rms
values (or you can solve them from first principles... it's
I=exp(-k*t)*cos(omega*t) for a damped sinusoid in an RLC)... watch out
though, TC's don't necessarily have nice exponential decay. See below.
> This assumes voltage drop across spark gap is neglible which I guess is
> true once the current flow is established.

Assuming the secondary is in place an its all tuned correctly. Ignoring losses and higher order terms, the envelope is cosine and if its an integer of a 1/4 cycle the rms value is half the peak.
ie 1/1.414 * 1/1.414.

Of cause the actually envelope is determined by quench, streamer loading and circuit losses (SG etc) as you suggested.

Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400