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Re: New coil not working

Tesla List wrote:
> 
> >From erc-at-coastalnet-dot-com Sat Nov 30 10:10:54 1996
> Date: Fri, 29 Nov 1996 22:23:18 -0400
> From: "George W. Ensley Jr." <erc-at-coastalnet-dot-com>
> To: tesla-at-poodle.pupman-dot-com
> Subject: New coil not working
> 
> It worked!
> 
> For about 15 seconds my new coil, my first, did what i expected. It produces
> branching arcs about 12 inches in length and looked as if some tuning and
> bigger caps would do the trick. Then it sputtered to a stop with only the 5
> static gaps showing any action at all.
> 
> Here are the specs.
> 
> 20a variac
> 
> 12kv 120ma neon
> 15 turn choke 2ea on ferrite cores
> 
> series/parallel cap .002uf
> 24 ibc root beer bottles ( ? brown glass)
> 
> 5 static gaps .021in
> 
> 13.5in 30deg spiral primary 11 turns
> 4.25in inner dia. 13.5in outer dia, 1/4in spacings
> 
> 3.125in dia. 1062 turn 24in 24awg secondary
> 
> I was taped in at the 11th turn and made it only to 3/4 power on the variac
> before problems appeared. I feel like i punched a bunch of holes in the caps
> and they are already history but my vom says they are ok.
> 
> any ideas?
> 
> I have since replaced the brown glass salt water caps with clear glass and
> have had no better results. my attention is now turning to the gaps. they
> are 5 1/4-20 bolts with cap nuts serving as the electrodes. i do see carbon
> deposits and am wondering if this is the problem
> 
> .
> ____________________________________________________________________________
> _________
> -.. . -. ....- --.. .--. ---   --. . --- .-. --. .   . -. ... .-.. . -.--
> GEORGE W. ENSLEY
> ____________________________________________________________________________
> _________

George,

When glass caps fail, the typical mode is arc-over through the
dielectric which shows up only under stress. Measuring with a low
voltage VOM will not show any problem. When they fail, you'll usually
see an orange glow where the glass is overheating and breaking down,
although with dark brown glass, this might not be readily evident. When
tis occurs, the typical failure mode is for the gap tp cease firing or
to fire only sporadically. 

You may want to try using stainless steel capnuts or short pieces of
copper tubing for the gaps. If you''ve formed carbon (or some other
black oxides) in the gap area, these may prevent the gap from quenching
properly, especially if these become incandescent while the gap is
firing. This has the effect of removing significant power from the
secondary. Hopefully, your transformer is not beginning to fail... 

Safe coilin' to ya!

-- Bert --