From: richard.quick-at-slug-dot-org (Richard Quick)
Date: Tue, 21 Mar 1995 00:58:00 GMT
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Quoting Ed Sonderman:
ES> Thanks for the response yesterday regarding input power and
ES> capacitor size/rating.
Hey, No Problem. I was sorry to hear about you blowing the cap.
ES> I need to decide where to go from here.
ES> Power is what it's all about.
Yup. Other's may argue, but I won't. Power is what it is all
about. I will one up you: it's about "bulletproof in your face
ES> I have a primary, secondary and toroid capable of producing
ES> at least six foot discharges.
ES> I don't have transformers or capacitors to support this.
Nope. If you had been slightly less rambunctious you could have
obtained, and perhaps sustained, 60 inches of discharge from the
system as designed, built, and powered. I never stated that
longer sparks were possible, but I never denied it either. You
recorded 50 inch discharges, but then again you never got up to
that goal of 2.0 kVA input power. You are quite correct that your
primary/secondary/discharger will produce in excess of 72 inches
of discharge on occasion. However, you are also correct that
producing these discharges mean producing high peak powers, which
requires a rock solid step-up transformer and capacitor(s).
ES> I was seriously considering going down to 9kv and fixing my
ES> shorted capacitor.
In the short run this will keep you sparking without worry. You
won't have a cap blow if you drop your voltage down. Regardless,
long or short, you should unroll and repair the cap. It is a
"boat anchor" now, but if patched it will hold a cash value in
excess of $75.00 (closer to $100.00).
ES> As you stated going down in voltage isn't really the best
Not in the long run. In the long run you want to go up in
voltage, and down in frequency.
ES> I think I need to make some more capacitors.
I agree here also.
ES> I want something that I can run at maximum power for 2 to 5
ES> minutes whenever I want - without worring about ruining
ES> something. I see two options. One is to fix my shorted
ES> capacitor and build two more just like it. Then I would
ES> have four .018mfd capacitors that I could use in series/
ES> parallel for .018mfd total. I would feel confident
ES> running this combination at 12kv or 15kv - with only 6 or
ES> 7.5kv across each cap.
Another thought: if you build up to six of these rolled caps, you
can place three of them in parallel for a bank of about ~.054 uF
total, then place the two banks in series. Your total capacitance
will be around .027 uF good for about 20kv. You can run 15kv
across this bank without any difficulties or limitations. A power
supply that provides 15kv 150ma will work very nicely, with the
total energy processed across the dielectric at about 2.25kVA.
The problem here is pretty simple though, once you get your
capacitance nice and solid, your neon power supply will fail.
2kVA almost seems like a threshold in Tesla Coils: below 2kVA
and everything (gaps, choking, filters, power supply, and even
tank capacitance) is relatively simple. Above 2kVA and the peak
powers get to the point that a kickback will take down an entire
neon bank in one shot. If 2kVA and above is where you want to
operate, forget the neons and get a better step-up transformer.
Again, for the money, and the reliability, I like the pole pig.
ES> The other option I see is to make two new capacitors using
ES> .090 poly and run these in parallel for .02mfd. I would
ES> think these should stand up to 12kv - I don't know about
ES> 15kv with a high duty cycle.
The polymer information supplied by Ed Harris points to thinner
dielectrics, not thicker, for better capacitors. I would have to
say that the other option would be a completely different
capacitor design (flat stacked plate) or, plunking down the $$$
and having Condensor Products, NWL, or Plastic Capacitors make a
custom unit. Sizable high-voltage custom capacitors are cost
effective if you consider your time, your cost for construction
materials, reduced incidents of failure (they are built in
commercial clean rooms), and the high Q factors.
___ Blue Wave/QWK v2.12