Re: Coil Failure

• To: tesla-at-pupman-dot-com
• Subject: Re: Coil Failure
• From: Alex Crow <user-at-pupman-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Fri, 14 May 1999 16:28:47 -0600
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Christoper:

Your problems seem quite simple here: Your description of the spark gap
seens to be the first item of concern. You have 7 gaps of 0.25 inch each,
which totals 1.75 inches! This is way, way too wide. At 10kV my *total* gap
spacing is only 0.25 inches with 5 gaps. Your gap will not fire until about
62,000V, which is way too high and will soon destroy your caps and your
neon. This is why your caps are making such a big display - the 'gap' they
provide (ie between the top terminals and the water) is obviously firing
instead - and you are lucky that you haven't blown a bottle up yet!
Basically all your power is being wasted here - every spark across the caps
is discharging them nowhere useful, bypassing your primary circuit. I would
think it's very, very loud too!

Also, why did you hammer the tubes flat? I can't quite imagine what this
would look like, whether you mean totally flat or just squashed slightly at
the ends to prevent discharge there. The electrodes should be round in
order to prevent excessive ionisation, premature discharge and bad quuenching.

All in all, *dont* try another run until you have checked the caps for
damage, rebuilt the spark gap and tested its voltage on its own (the full
gap setting should break down when connected *just* across the NST output
and nothing else). Otherwise something will go *pop* and as someone on this
list once wisely said to me (Terry?) it will be your most cherised or
expensive part!.

Good luck

Alex

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