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Re: (Barry Vs. Fr.Tom) Differing advice
From: Benson_Barry%PAX5-at-mr.nawcad.navy.mil[SMTP:Benson_Barry%PAX5-at-mr.nawcad.navy.mil]
Sent: Tuesday, November 25, 1997 12:32 PM
To: tesla-at-pupman-dot-com
Subject: RE: (Barry Vs. Fr.Tom) Differing advice
Hi Joshua, All,
Fr. Tom is correct that about 0.079 uF will get the max. out of these
transformers. Since the CSI capacitors cost about $200 each the quantity of
4 was all that I could afford and is what I spec.d for my system as it gave
the 56" spark. Maxwell recently quoted me a price of $283 for a 0.06 uF
(#31393) polypropylene and Kraft paper in castor oil plastic cased capacitor
rated at 40 kVDC in a quantity of 10 (group buy??). I believe that this is
the same one that Bert Pool used in his magnifier. The CSI capacitors are
very nice but too expensive. The capacitors sold by DC Cox sound even
better with extended foil and polypropylene in silicon oil but the price is
high and the manufacturer (and manufacturer spec's) are unavailable.
As for the DC voltage rating I would never go below 30 kV without a
safety gap across the capacitors. I have never lost one of the 30 kVDC
rated units that I have although I have never used a safety gap. After
reading about the experiences on this list I will always use a safety gap in
the future!
Barry
Barry, Fr.Tom, All,
I recently asked fellow coilers what sized caps they used with two H&R
transformers in series.
My calculations say .079uf and so does Fr. Tom. yet you (Barry) used .04
uf rated at 30 kV DC
for the task.
I realize the coil will work at lower ratings but which value is more
desirable, one that draws the most
possible current from the transformer or one of lower rating?
Also 30 kV DC means half that rating AC, so isn't that really pushing
the caps. voltage rating?
Have you ever had one of these cap blow?
In addition, how much does one .01uf -at- 30 kV DC cost from CSI?
Thanks for the advice from both of you, I just want to get the biggest
bang for my buck.
(and that's what all this is about anyway, right?)
____
/\/\ ((____)) /\/\/\/\ Joshua "Flux Boy" Resnick
/ | | \ \ http://www.wpi.edu/~seraphim
/ | | \/\/\ \ __ http://ece.wpi.edu/~seraphim
/ ____| |____ \
|||||||||||||| \ "Two parts oxygen and one part
lovin'."