TRANSFORMERS & CAPS AGAIN
Subject: TRANSFORMERS & CAPS AGAIN
From: richard.quick-at-slug-dot-org (Richard Quick)
Date: Wed, 22 Mar 1995 02:03:00 GMT
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* Original msg to: Esondrmn-at-aol-dot-com
Quoting Ed Sonderman:
ES> I found a friend who just retired from the local power
ES> company. He gave me a name to call and I'm trying to get a
ES> 5kva transformer. It's called a fourteen/four. 14,400 v in
ES> with 240v out. Sounds just like what I need.
It does sound like what you need.
ES> I called three commercial capacitor companies this morning.
ES> If I have to build two more caps, I figure I can spend $150
ES> to $200 and come out just as well. Two of the companies are
ES> going to call me back. Brian at CSI Capacitors in San
ES> Marcos, CA said he has .02mfd pulse discharge capacitors
ES> rated at 60kv DC that should work. They are 3.0" in dia.
ES> and 16.0" long.
It does not sound good. You want voltage ratings quoted in KVAC
pulse, not.. "I have a 60kvdc that will work.".
ES> The price is $400.00.
Too much. I paid $300.00 a couple of years back for two .1 mfd
45 KVAC pulse caps (not .01 mfd). These caps are 6 inches in
diameter and 14 inches long. Inflation or no, he gave you some
ES> He says no guarantee when used in Tesla coil applications.
Nobody will guarantee a capacitor in the Tesla tank circuit. That
should tell you something about this circuit, no? But companies
can, and do, design and build capacitors to operate with limited
duty cycles in the Tesla tank circuit. These capacitors will have
AC ratings (though there will be a Dc rating also), and will use
pure plastic film dielectrics. So ask some more questions:
"Do your capacitors have 100% pure plastic film dielectric?"
If no then ask, "Will you make me a capacitor that does have a
100% pure plastic dielectric?" How about, "What is the AC
rating of this capacitor?"
The plastic film dielectric type is not so important as long as
it is polyethylene, polystyrene, or polypropylene. This is one
area where I would be willing to trade off a couple of percentage
points in dissipation factor as long as I am assured that a 100%
plastic film construction was used, and that the capacitor
carried a KVAC Pulse voltage rating.
The oil type used in the construction is still typically a light
mineral oil, but some of the hotter manufacturers are now using
HV silicone oils.
ES> Sounds like too much money to me.
Yeah, and I think I would find somebody who says; "I can't
guarantee this capacitor in the Tesla tank circuit, but this
capacitor is designed and built with such applications in mind.
It carries an AC Pulse discharge rating, and we have sold this
capacitor type to coilers before."
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12