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Re: Top Toroid +Ayrton Equation



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: Thursday, February 06, 1997 12:41 AM
> 
> Subscriber: jim.fosse-at-bdt-dot-com Wed Feb  5 22:35:31 1997
> Date: Wed, 05 Feb 1997 04:57:06 GMT
> From: Jim Fosse <jim.fosse-at-bdt-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Top Toroid
> 
> >> Not at all. If the gap has a more-or-less fixed conduction voltage,
> >> then losses scale as I. With a normal resistance they scale as I^2.
> >> Case 1 is V*I, Case 2 is I^2*R
> >>  
> >Just wanted to point out that the fixed conduction voltage scenario is
> >essentialy what would be predicted by Aryton's arc equation and leads
> >to a linear decay rather than an exponential one  for a single LC
circuit.
> >
> Hi Ed,
> 	Would you care to post Aryton's arc equation for us? Does it
> have a variable resistance vs current term?  Any thought on modeling a
> spark gap for tesla use?
> 
> 	Regards,
> 
> 	jim

Sure Jim,

	Actually I posted it twice before with little comment from the list.
One of these times I even included a quickbasic program to simulate the
behavior a arc-type gap in an RLC circuit (should I re-post?).

	Anyway, from "Industrial Plasma Engineering"-J.Reece Roth p372:

	Vgap = A +B/I^(n)

where 
Vgap is the voltage across the gap
I is the gap current
n is some exponent which is usually in the range 0.5-1.5
and
A,B are some constants which depend on the gap 
geometry, gas type and pressue

"A" might be 40-200volts for some typical arcs

Linear decay of the RLC waveform is seen even (and especially)
if only the constant voltage term "A" is included. In this case,
the differential equations can be solved exacty!

What do you think?
-Ed Harris