Re: Vortex gap loss measurements

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Dan,

Thanks to you and Bert for some fine posts. in reply to your
question:

On 3 Sep 00, at 18:37, Tesla list wrote:

> Original poster: "Daniel Boughton" <daniel_boughton-at-yahoo-dot-com> 
> 
> Malcom:
> 
> It is obvious that the gap cannot be described via
> linear resitive model(see my additional comments to
> Gary). Plasma is a very unique thing. I have worked
> for years with RF generators, impedance matching
> networks to plasma chambers for silicon etching. With
> a rich variety of gas mixtures, pressures,
> temperatures, volumes, and frequencies a wide variety
> of impedance responses are dynamically encountered
> (primarily capacitive). The matching networks are
> automated to analyze the load (chamber) impedance by
> detecting the foward and reverse VSWR and adjust the
> capacitors (vacuum variable) for max power transfer.
> The chamber was in a constant flux (as far as
> impedance goes) when ignited. Even so, a mathematical
> model of behaviour was derived which acurately
> predicted the behaviour across all variables. This
> mathematical model was loaded in the firmware to
> automate the match. The result was to have precise
> tuning in a very fast time response (due to
> microprocessor calculation speed and servo motion to
> adjust the capacitor).

<snip>
> You noted in your message that "The gap is dissipative
> but that is where the similarities with resistance
> end. I analysed this and wrote a note on it several
> years ago." How do you mean dissipative? Do you mean
> heat loss? Secondly, don't take me wrong (I agree as
> you can tell from my previous statements) but how did
> you determine that the gap (I think you mean arc)is
> dissipative and that is where similarities end? How
> did you conduct your experiment and do you still have
> data?

I do mean heat loss (and light, sound which springs from the 
heat) etc.  I meant that the gap cannot be a constant 
resistance and cannot therefore be used in equations which 
assume such a resistance such as those used to derive a figure 
for Q. My experiments were conducted in much the same way as 
Gary's except that I used a scope aerial to see the results 
(there was a notch filter planted across the input to get rid 
of mains artifacts). I then tried several different coils with 
the same capacitance and noted the different slopes. The best 
of these was a 350uH litz coil which rang with the cap for 
over 1mS before the gap went out. I then attempted to 
calculate Q based on the energy loss between peaks and 
discovered that "Q" was in fact dependent on the absolute 
amplitude - in other words, changed from cycle to cycle with 
the least percentage of energy loss from one cycle to the next 
occurring when the amplitude was highest. I inferred from this 
that it was a good idea to start out with the highest voltage 
in the primary you could get away with and from the slope of 
the decrement inferred that a high L/C ratio was equally 
desirable. Nothing more sophisticated than that.

Regards,
malcolm