Re: Dielectric Constants and Breakdown Voltages (fwd)

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Dielectric Constants and Breakdown Voltages (fwd)
From: Tesla List <tesla-at-stic-dot-net>
Date: Thu, 13 Nov 1997 09:22:17 -0600
Approved: tesla-at-stic-dot-net

From:	Adam [SMTP:absmith-at-tiac-dot-net]
Sent:	Wednesday, November 12, 1997 11:04 AM
To:	Tesla List
Subject:	Re: Dielectric Constants and Breakdown Voltages (fwd)

>Hello all,
>   With regard to the puncture voltage an dielectric 
>constant of mylar -- 7500 v ? (not 750 v ? )

>   In either respect --- I recall some comment 
>that mylar was not good for caps for T.C. service --
>if  this is so (meaning my memory is not failing me) :>)
>howcome ??? --- It seems worthwhile esp.if the 7500
>V/mil is accurate ---

The 7500V/mil is correct, making mylar an excellent dielectric for high 
voltage DC capacitors.  Unfortunately, the extreme polar nature of 
polyesters (mylar included) gives them terrible AC losses.  The molecules 
rotate back and forth with the voltage swing, heating the material very 
rapidly and melting it.  Put aluminum foil on the insides and outside of 
a polyester coke bottle, apply current from a neon transformer and watch 
the bottle melt in seconds!!

-Adam

--------------------------------------------------------------------------
Adam Smith
absmith-at-tiac-dot-net
Epoch, Inc. Digital Music Project

www.tiac-dot-net/users/absmith/     Now with MP3!     Musik. Macht. Macintosh.
--------------------------------------------------------------------------