mixed dielectric cap

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: mixed dielectric cap
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 24 Sep 1997 18:06:45 -0500
Approved: tesla-at-stic-dot-net

From: 	Gwyn Zucca[SMTP:gwyn-at-tcbod.demon.co.uk]
Sent: 	Wednesday, September 24, 1997 12:29 PM
To: 	tesla-at-pupman-dot-com
Subject: 	mixed dielectric cap

Hello all,

I am considering building a couple of high power discharge capacitors, 
to a design that I have done some previous experiments with. The design 
uses 1mm (40 mil) polypropylene sheet as the dielectric with grease 
proof cooking paper between the foil and the poly as a wicking agent.
This mixed dielectric construction is of similar form to that of 
professional build, but the grease proof paper is a substitute for high 
density capacitor paper. The experimental caps thus far have been of the 
flat plate type, and of a sealed, oil immersed form. The proposed new 
ones will be 65nF in capacitance, 40Kvdc working, to be used in series 
in a symmetrical equi-drive type tank circuit. This covers the basic 
detail. 

What I would like to know is, has any one else constructed caps of a 
mixed dielectric type, and what experiences have they had. I think that 
home made mixed types offer the advantage of better oil penetration and 
so help expel trapped air, in which corona tends to form. I also agree
with the view voiced by others on the list that certain oils can enhance
dielectric properties.

any comments welcome ( useful ones anyway!!! )

See ya...

Gwyn