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Re: Quenching


From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: 	Wednesday, September 10, 1997 5:53 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Quenching

I<< snip>   Without going through all the steps, I finally tried the air jet 
> at full pressure. Now the gap was very loud and bright, output had 
> sunk to a real low, and I actually achieved quench at the end of the 
> second ringup with no breakout. It is clear this was a totally useless 
> setting because while the quench looked excellent on the scope, the 
> gap was dissipating the bulk of the power. This was borne out by the 
> abysmally short discharge to the ground wire. BTW, the full air jet 
> was so violent the spark was considerably displaced from the centre 
> of the gap electrodes.

Malcolm,

By second ringup, do you mean the second notch; the second
complete transfer of energy to the secondary?  If so, this should
be the perfect place to quench I would think.  Could it be that some
firings were being skipped, or missed?  Could this be what some
people refer to as "overquenching"; the gap is sometimes prevented
from firing due to excessive air?

>snip>    I now think that the degree 
> of quench he was having to apply to stop power arcs was hindering the 
> output of the coil. It seems to me that the way around this is to 
> choose a bigger cap to load the supply more heavily so the air supply 
> could be moderated to the point where it served the tuned circuits 
> best.

I have so rarely seen power arcs in my TCs, that its hard for me to
comment.  I agree large caps should help prevent the power arcing.
 
>     For my coil it looks as if a quite moderate air jet is best for 
> tuned circuit behaviour. Question is: will it also be best for 
> stopping transformer arcs in the gap? If more air is required to stop 
> the arcing, it seems I could do better in matching the primary cap to 
> the transformer. Be interested in comments anyone else has to make on 
> this.

By using 120BPS sync gaps and resonant charging,  the gap fires
at or near the zero crossing point of the 60Hz AC cycle, and power
arcs are unlikely.

John Freau
 
> Malcolm
  >>