FIRST capacitor, please advise/help
From: Sulaiman Abdullah[SMTP:sulabd-at-hotmail-dot-com]
Sent: Thursday, December 04, 1997 3:54 AM
Subject: FIRST capacitor, please advise/help
Hello all, I sent an e-mail with attachments that got screwed-up,
so here's my request again. Please send me any comments/thoughts.
I'm building my FIRST Tesla Coil,
I have built, and destroyed, a couple of small/test capacitors.
Now I'm building my FIRST real primary capacitor.
My power source is a 15 kV centre-tapped 30 mA 50 Hz NST.
I calculated 6.3662 nF as the optimal value to match my NST.
The design is a basic vertical stacked-plate, in oil.
DIELECTRIC 22 pieces of 300mm x 300mm x 3mm HDPE.
PLATES 23 pieces of 280mm x 250mm x 0.4mm Aluminium.
SPACERS 21 pieces of 1" x 1/4" x 300mm Aluminium stock.
2 pieces of 1" x 1/4" x 400mm Aluminium stock.
(300mm plus 100mm for external connection)
2 pieces of 1" x 1/8" x 300 mm Aluminium stock.
( for two ends of capacitor)
OIL not yet decided.
When all these pieces are assembled there will be 22 parallel plates
of effectively 250mm x 200mm for a total theoretical value of
22 x 8.854 x 2.2 x 0.25 x 0.20 / 0.003 = 7.142 nF.
The tracking/arcing distance should be 50mm at the ends,
and 2 x 25mm upand down.
If you can understand the above then please help me by pointing
out anything that should be changed before I assemble it.
Questions that come to me are ;
1 Is 50mm at the ends enough?
2 Is 25mm at the top/bottom enough?
3 Based on your EXPERIENCE how many kV should such a capacitor
be able to handle.
I'd rather have a long-lasting pulse-capacitor than one of the
theoretically correct value, so I'm willing to trim the plates as
you may reccomend.
I really want this to be a long-life component as I immagine other uses
in future such as high-power high spark-rate RSG Tesla use,
can-crusher,magnetisation pulses etc.
PLEASE HELP ME TO AVOID AN EXPENSIVE MISTAKE.
ALL COMMENTS/SUGGESTIONS ARE VERY WELCOME.
Thanks ... Sulaiman