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Re: An Interesting Problem



---------- Forwarded message ----------
Date: Tue, 14 Oct 1997 14:50:17 -0400
From: Thomas McGahee <tom_mcgahee-at-sigmais-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Cc: MALCOLM-at-directorate.wnp.ac.nz
Subject: Re: An Interesting Problem 



----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: An Interesting Problem 
> Date: Monday, October 13, 1997 6:06 PM
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Tue, 14 Oct 1997 09:43:45 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: An Interesting Problem
> 
> Hello All,
>             I've some up against an interesting conundrum that I 
> expect others have struck at odd times (no, I haven't scoped it).
> I recently fitted more top C to my largest coil, added a turn to the 
> primary and removed about 20% of the primary capacitance to tune it 
> back up. With the radius of curvature at the top it is now having 
> trouble breaking out at the energy level the primary is running at
> (around 2.7J). When it does, it throws a few hot ones, stops dead and 
> either continues to burp in this fashion or needs to be switched off 
> and on again at the wall to get the gap to fire again. The primary 
> voltage is rather low, *but*, it does run reliably and steadily if I 
> add a bump or small point to the terminal in which case it now throws 
> a steady streamer (which waxes and wanes in length as usual).
>     The question: if the gap can clearly fire at this setting, what 
> is stopping it in its tracks when the thing does break out on 
> occasions? Any answers?
> 
> Malcolm

Malcolm,
If there is no breakout, then where did the energy "go"? My guess is that the
secondary is returning the energy to the primary, and that in your case the
"phasing" of this return energy is such that it is "bucking" the voltage at the
gap. It may even be partially charging the cap to the "wrong" polarity
(phase-wise) if the return energy is back-feeding through the (as yet
un-extinguished) spark gap. Either of these two scenarios would cause at least
some of the symptoms you mentioned.

BTW, note that Tesla was building his really big coils NOT to produce spark,
but to build up a tremendous "push" between earth and the topload. The opposite
of what most coilers are doing.

FWIW
Fr. Tom McGahee