mixed dielectric cap (fwd)

To: tesla-at-pupman-dot-com
Subject: mixed dielectric cap (fwd)
From: Tesla List <mod1-at-pupman-dot-com>
Date: Sun, 28 Sep 1997 14:34:56 -0600 (MDT)
Approved: mod1-at-poodle.pupman-dot-com


---------- Forwarded message ----------
Date: Sun, 28 Sep 1997 13:59:31 -0600 (MDT)
From: Chip Atkinson <chip-at-pupman-dot-com>
To: tesla-at-pupman-dot-com
Subject: mixed dielectric cap

From: 	DR.RESONANCE[SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: 	Thursday, September 25, 1997 11:04 AM
To: 	Tesla List
Subject: 	Re: mixed dielectric cap

To: Gwyn

Mixed dielectric caps will work for a time but are usually prone to failure
due to the different k factors.  Also, if you touch any of the foil parts
with your skin you add skin oils which will eventually cause failure. 
Finally, the best way to remove air is with a vacuum.  After pumping there
is also a "curing" period in which all the air bubbles finally work their
way out.  Best way to do this is with a small vibrator shaker table
arrangement.  For best results the foil should be 1-2 mil thickness which
is too thin to handle with human hands.  If all of this sounds like trouble
-- it is.  Commercial caps are expensive but the only way to go unless you
are on a high school budget.  Hope you have considered the above or else
there is only a question of time to failure.

DR.RESONANCE-at-next-wave-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
> 
>