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Re: HV Xfmr Protection networks
From: Edward V. Phillips[SMTP:ed-at-alumni.caltech.edu]
Sent: Tuesday, July 01, 1997 2:43 PM
To: tesla-at-pupman-dot-com
Subject: Re: HV Xfmr Protection networks
" Ed -
Did you test the "Vitamin Q" capacitors at 10 KV DC? What were the results?
How did you test them for dissapation factor and RF performance?
What were the results?
>
I have had difficulties with these tests.
John Couture"
If you mean did I test leakage current, the answer is
indirectly. Charged them to 15 kV and let them stand for an hour,
then checked the voltage which was still about 12 kV, as measured
by a voltmeter with 100 meg total resistance.
As far as resistance factor is concerned, for large values
of capacitance I form a parallel resonant circuit and measure the
effective shunt resistance at resonance. From knowledge of the
Q of the inductor you can guess what it's shunt resistance is,
and then from that calculate that of the capacitors. Seems to
work quite well for me. Tests, of course, are run at very low
RF voltage. I suppose that there is a possibility that with
much higher applied voltage the contact resistance of an inserted
tab capacitor might go down, but for extended foil shouldn't
make any difference except when the dielectric is voltage
sensitive as in the various Hi K titanates.
Ed