Re: OLTC II Initial calculations

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Stephen Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>

At 17:32 07/05/03 -0600, you wrote:
>Original poster: "Malcolm Watts by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
>
>Hi Stephen and other output voltage enquirers,
>                                                It is well known that
>you cannot judge output voltage by spark length in a disruptive TC.

In the calculation that I posted, I didn't do that. I used John's spark 
length formula (I figured it would work since it was one of his coils :) ) 
to work back fron his quoted spark length and find the power. Since he also 
quoted the bps, I could find the bang energy. From the dimensions he posted 
I had a rough idea of the secondary capacitance and so could work out the 
output voltage from the bang energy and capacitance.

>I'd urge anyone who
>wants to see this for themselves to do some single shot expts.

I have been doing these with my OLTC. I designed it to be adjustable from 
2bps to 1200bps. Basically I found that at low breakrates the spark length 
agrees well with the peak output voltage and the dielectric strength of 
air. (The 1.1kV/mm thing) Beyond about 300bps the sparks start to grow 
until at 1200bps they are about 12".

With bigger coils, the streamer growth obviously starts at a lower bps. My 
larger coil did about 10" on single shots, 17" at 100bps, and 30" at 
400bps, with roughly the same bang energy in each case.

All measurements are the longest distance it will jump from a breakout 
point to a grounded point, at least once in a 1 minute test.

Steve C.