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Re: Arc length vs pwr



Tesla List wrote:
> 
> >From MALCOLM-at-directorate.wnp.ac.nzWed Oct 16 22:23:39 1996
> Date: Wed, 16 Oct 1996 09:37:39 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: Arc length vs pwr
> 
> A quick comment on this:
>       I think arc length would have to obey a square law at least as
> far as upping power is concerned. The longer the spark, the more
> power dissipated along it both in maintaining ionization (width) and
> length (series resistance). I think one further order of power loss
> occurs in the gap when upping power levels. I do think though that
> primary things can be tailored to reduce this loss - it will be
> different for different gap systems in my opinion.




I believe at one time I made a statement about the spark length versus 
energy was nearly related it to the cube of the radius of the sparking 
circle.  This was of course a genralization, but you have probably hit 
the real causitive agent for the inverse sqaure law failing to account 
for the energy vs spark fall off.  Naturally the inverse square law 
applies in the ideal case, but the scaling up of input energy affects the 
gapping most horribly!  As power is upped, so the gap losses increase, 
but far from a nice linear basis.  Thus, the higher powers show a gross 
reduction of spark length per unit input energy over and above the 
expected inverse square law. 

 R. Hull, TCBOR
> 
>      On the lumped vs distributed thing for the secondary: the more
> top-C you have, the more lumped it gets as the secondary current
> becomes uniform and hence 0.5LI^2 applies. That measure of magnetic
> energy cannot apply in a distributed circuit as the current is not
> uniform along the length of the coil. There would be (in my opinion)
> an optimum top-C for a given secondary and bang size because several
> things happen while increasing terminal capacitance: (1) the
> secondary inductance is becoming more effective (Q increases), (2)
> voltage holdoff is increasing (assuming more C = greater radius of
> curvature (ain't necessarily so), and (3) output will eventually
> decrease due to energy limitation. It would be jolly nice to quantify
> this optimum R.O.C. and size.
> 
>      On tuning: there is one subtlety I have used where Lp and Cp are
> more-or-less fixed: raising and lowering the top terminal can
> dramatically alter secondary fr.
> 
> fwiw,
> Malcolm

Malcolm

I have also noted that as the top terminal is raised or lowered, Q of the 
resonator system is also either raised or lowered.

R. Hull, TCBOR