Re: Another first coil story

Subject:  Re: Another first coil story
  Date:   Fri, 6 Jun 1997 03:35:00 +0500
  From:   "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
    To:   Tesla List <tesla-at-pupman-dot-com>

On Wed, 4 Jun 1997 22:02:55, -0500 MATT MCARTHUR

> Hello All,
> I have been silently watching this list for a month or so now and I
> just completed my first coil.  I am having a few problems with it 
> though.  The main thing is that I am only getting a weak little 
> 6" (thats inch) spark, if that.  As far as I can tell I have achieved 
> resonance, I think, since I only get the 6" spark when the primary is
> in the perfect spot (tuned).
>   The setup I have is a 10KV 23mA OBIT tranny, 5  1.2nF salt water
> beer bottle caps ( I built a plate glass cap but roasted it due to 
> poor design) 2 series gaps with .020 inches gap each.  My primary
> is made out of 1/4 inch copper tubing, 7" diameter, 5" tall. The
> secondary is 3 1/2" PVC pipe, approx 12 1/4" long with about 500
> windings of .025" enameled wire. The output terminal is pretty cheap,
> it is a 60 watt deco light bulb (5" in diameter) covered with aluminum
> foil.
>   The best guess I have to the wimpy sparks is bad coupling. The 
> secondary sits about one inch from the BOTTOM of the primary.  I had 
> just read a post that said something about the secondary for lower 
> powered coils being 1 1/2" ABOVE the primary to enhance the coupling.
>   Could somebody please put me back on track!?!?!?

Hi Matt! I would say your first problem is your not getting enough 
energy into your coil. The proper capacitor for a 10KV 23 ma. obit
is 0.0043 ufd.! The salt water beer bottle caps are not only too 
small in terms of capacitance but they are notoriously leaky as 
well! Why not make yourself a polyethylene film and aluinum foil cap.
Their much more efficient and easier to move too. A proper top 
terminal for your coil would be either an 8 inch sphere or at least
a 2 X 8 inch toroid. I would say beef up your capacitor before 
playing with the coupling.


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