Re: Tesla Secondary Voltage

To: tesla-at-grendel.objinc-dot-com
Subject: Re: Tesla Secondary Voltage
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Date: Thu, 23 Nov 1995 10:50:43 +1200
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Ed Sonderman writes....

> Subject: Tesla Secondary Voltage
> 
> Does anyone know approximately what the secondary voltage is on a coil that
> is producing 5 to 6 feet of spark?  I have seen some discussion on this but
> never seen any numbers.  Is it like 2 million volts?
> 
As far as I know, it's nothing like this figure. In a DC situation
yes. But spark length in a coil is very dependent on power throughput.
All the analyses I've seen suggest that the figure is much lower. You
can put a theoretical maximum on it based on energy conservation :

    Vo = Vi x SQRT(Cprim/Csec)
    
Some transmission line analyses suggest the real figure is somewhat 
below this. This is reasonable if you consider that not all the pri-
mary energy ends up in the secondary in a single (quarter) cycle of
oscillation.
    My experiments suggest you can get a reasonable ballpark 
estimation based on single-shot spark length (with a distance
relationship of 2.5 - 3 feet per million). My large coil has
a theoretical maximum as above of 550kV but throws solid arcs
4 to 4&1/2 feet. A friend of mine in Britain who has access to
an analytical program written by the Corum's has run the figures
for my coil through it. The results, taking into account M, k 
Cp, Vcp etc.etc. shows somewhere in the region of 400kV. 

Malcolm