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Re: Sparklength inquiry


  Bart, Greg -

  I agree the equation (Vs/1000/65)^1.43 is not correct. It should be
(Vs/65000)^1.43 where Vs is the secondary volts or
(KVs/65)^1.43 where KVs is the secondary kilovolts.

  This equation is an empirical equation based on real coil test data from
many coilers. The reason for the non-linear 1.43 power is because the spark
length is dependent on both voltage and the ionization of the air path from
the previous spark. Some day it may be possible to equate the ionization in
a more accurate manner.

  To my knowledge this is the best equation presently available for TC
spark length. It will probably change when more accurate data from coilers
becomes available. It appears to be working well at present. It can be
related to breaks and power by

  Watts = .5 Cs Vs^2 BPS  or  Vs = sqrt(2 watts/(CS BPS))

  Hopefully coilers like you will develop a better equation.

  Tesla coils are like women, they are more fun to play with than to try
and understand.

  John Couture

------------------------------

At 04:58 AM 9/22/98 -0600, you wrote:
>Original Poster: Greg Leyh <lod-at-pacbell-dot-net> 
>
>> Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net>
>
>> > Finally, the equation  (Vs/1000/65)^1.43  is incorrect
>> > for Tesla Coils, since both Vs *and* BPS are first-order
>> > contributors to the total spark length of a real coil.
>> 
>> Yes, that's why I was trying to manipulate BPS into the
>> Es equation above to accomodate for the bps
>> contribution. No luck. After the post I threw in some
>> high bps values which I had not done before, and the
>> sparklength was "dreamy", but not realistic, at least on
>> my coil.
>
>Awhile back, someone (perhaps Mark Rzeszotarski?)
>came up with a curve fit of power consumption vs
>coil scale.  I remember that it seemed to fit the
>real-world data fairly well, and that it's baseline
>showed that coil power increases with the *square*
>of the coil dimensions.  
>If we assume that all coils under consideration are
>operated at their optimum BPS (to get BPS out of the
>equation) then arc length seems to be more directly 
>related to output power, as the total arc volume must 
>be super-heated in order to be an arc in the first place.
>Doubling the arclength should increase arc volume by 8,
>but the square/cube law may help to conserve heat in the 
>core, possibly resulting in just a squared relationship.
>
>I tend to view the TC as a furnace in this way, and 
>more *power* is necessary for more plasma.
>-- 
>
>
>-GL
>www.lod-dot-org
>
>
>