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Re: Glass cap with polyethylene




From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Sunday, September 14, 1997 1:28 PM
To: 	Tesla List
Subject: 	Re: Glass cap with polyethylene

On Sunday, September 14, 1997 2:37 PM Bert Hickman
[SMTP:bert.hickman-at-aquila-dot-com] wrote;

> Alfred and all,
> 
> Actually, it's when materials with a significant difference in
> dielectric constants are combined that an unequal share of stress occurs
> on the dielectric having the lower k. In the case of mineral oil and
> polyethylene, the k's are quite close (k of about 2 - 2.3), so there's
> no large discontinuity in the electrostatic fields. However, if you add
> glass (k of about 5 - 7), it will significantly increase the voltage
> stress on the LDPE and mineral oil. This is even worse for if you have
> any entrapped air (k=1). 

In theory I can agree, BUT in practice if the polyethylene is thick 
enough to handle the applied voltage no breakdown will occur 
regardless if it is combined with glass or not.

 
			       Sincerely

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			   Alfred A. Skrocki
		  Alfred.Skrocki-at-CyberNetworking-dot-com
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