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Re: Glass cap with polyethylene
From: David Huffman[SMTP:huffman-at-FNAL.GOV]
Sent: Monday, September 15, 1997 1:32 PM
To: 'Tesla List'
Subject: RE: Glass cap with polyethylene
It should be noted that two different dielectric 'constants' will cause electric field disruptions. The oil which has a dielectric constant almost equal to polyethylene simply displaces the gas by filling in the cracks. If the cap is built with tight layers there is very little oil actually adding to the gap thickness.
My 2¢
-----Original Message-----
From: Tesla List [SMTP:tesla-at-pupman-dot-com]
Sent: Sunday, September 14, 1997 10:12 AM
To: 'Tesla List'
Subject: Re: Glass cap with polyethylene
From: Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: Saturday, September 13, 1997 9:02 PM
To: Tesla List
Subject: Re: Glass cap with polyethylene
On Saturday, September 13, 1997 10:21 AM DR.RESONANCE
[SMTP:DR.RESONANCE-at-next-wave-dot-net] wrote;
> To: Rich
>
> Using two different dielectrics in a cap is very bad. The electrostatic
> fields will not be uniform which could lead to local corona and hence a
> breakdown. Suggest using single sheets of plastic and then series
> connecting each subsection.
I find one major flaw in your logic, namely the fact that almost all
polyethylene caps used for TCs are in fact dual dialectric caps. The
polyethylene being one dielectric and the oil being the other. If
your logic was true then, all oil immersedimmersed polyethylene caps would
breakdown . In fact they rarely break down when built to tolerate the
voltages used.