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Re: Sparks (finally)
Hi Mike,
> The secondary is about 940 turns of #22 on a 6 1/4" HDPE tube and loaded
> with a 20" x 5" toroid made of corrugated drain tubing covered with
> aluminum tape. Primary is 15 turns of 3/8" copper tubing wound with 3/8"
> spacing into a 15 degree inverted cone. Inner turn is about 9". The rest
> of the tank is two .060 poly rolled caps wired in series and two cylinder
> static spark gaps with six .030 gaps in each. All this is bussed together
> with 3/8" copper.
>
> Today I went out and got two 15kv x .030 neons (900 VA) and hooked them up
> with 12 .030 gaps. Still no breakout without some coersion......
>
> Is anybody having problems with heating of the secondary? After a few sustained
> runs of about 3 or 4 minutes the secondary got pretty hot and the wire and
> polyurethane is bulging out in a few spots where I guess there is air trapped
> behind the wire. The poly seems to be holding up pretty well to the heat but
> there are about a half dozen bulges about the size of a quarter poking out now.
Whoa! Heating on the secondary at this relatively low power level? Mike, you've
seen my 6" coil. I am now pumping about 1.8 KVA through it and it doesn't even get
warm. It sounds like something on or near the wire has a high dissipation factor.
Our secondaries are nearly identical, except for the fact that mine is on an acrylic
former instead of a HDPE one. I also used epoxy to seal my wire, not polyurethane.
The HDPE should be better than acrylic. I guess the next thing that I would suspect
is something in the particular brand of polyurethane that you used. Other than that,
I can think of nothing else that would cause this problem.
Talk to you later,
Scott Myers