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Re: output

Tesla List wrote:
> 
> Subscriber: major-at-vicksburg-dot-com Sat Jan 18 22:32:36 1997
> Date: Sat, 18 Jan 1997 20:29:48 -0600
> From: RODERICK MAXWELL <major-at-vicksburg-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: output
> 
> Last night I ran my coil flat out, full power for the first time.
> After about ten seconds my spark output decreased dramaticaly. At first
> I thought I might have ruined the transformers, but after I turned off
> the coil for a few minutes and tried again spark output returned to
> normal! Does one of the more eperienced coilers know what the problem
> could be? I would like to be able to run more than ten seconds at a
> time.
> 
> 
> 
>      Secondary coil: 4" diammeter x 18" tall  (winding area) polysyrene
>      Primary coil: saucer coil, 30 degree pitch .25" tubing spaced .5"
>      Spark gap: six 3/4" copper tubing 3" long spaced ~.028" apart
> forced air cooling by
>       ac muffin fan
>      Neon transformers: two 7500vac -at- 30ma in parallel
>      Chokes: two ferrite bobbin core chokes wound with ~200 turns 24#
> magnet wire in
>      oil
>      Safety Gap: with center post tied to rf ground
>      Tank Capacitor: .003uf cap made of 1/8" thick poly in vertical
> plate configuration,
>      in mineral oil
>      Resistors: two 50watt power resistors in series with each leg of
> the transformers
> 
> [ Your spark gaps are getting too hot to quench properly.  Try putting
>   another muffin fan next to them and see how that works.  That's my bet
>   anyway.  If the gaps are way hot after a run, then they are causing
>   problems. -- Chip]
> 


Chip, et al -

  The effect is called pre-ionization in the spark gap. When the
metal electrodes get hot enough, electrons tend to 'jump' off the
metal with very little provocation (ie:voltage). So, the gap pre-
ignites at very low voltage where there is hardly any energy stored
in the cap (gap firing very early in the AC sine curve) hence, very
little energy going into the system. Viola, minimal coil ouput.

- Brent (bturner-at-apc-dot-net) "If all else fails, vaporize the tungsten."