Re: Di-electric Disaster

To: tesla-at-pupman-dot-com
Subject: Re: Di-electric Disaster
From: "Bill Parn" <parn-at-starpower-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Tue, 16 May 2000 08:23:51 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hello,

I read a great article on Terry's web site.

http://users.better-dot-org/tfritz/site/MMCinfo/rel/ this is the directory
where it resides, 5 or 6 scanned in pages.  More down below
for relevence.

----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, May 15, 2000 11:17 PM
Subject: RE: Di-electric Disaster


> Original Poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
>
> The dielectric dissipation of oil is irrelevant in a plastic dielectric
> capacitor.  It's the plastic's dissipation that matters, as that's 99.99%
of
> the stuff between the plates.
>
> The breakdown voltage of the oil is not really that critical either.  The
> oil's main function is just to displace air.  The types of failures in
home
> made poly/oil caps are typically:
> 1) Dielectric punctures due to either too thin poly or localized
> heating dor to partial discharge within the poly, or
> 2) An arc surface-tracking across the surface of the poly.
> In neither case would a super insulating oil have helped.
>
> I don't have the tables here in front of me but I think I recall seeing
that
> PE has a slightly better dissipation factor than PP.  But there must be a
> reason that commercial caps use PP exclusively in HV pulse discharge
> applications, perhaps it has a higher melting point.

Guessing but if you read the article referenced above, then PP might
be used because it is easier to get the aluminum vapor to adhere to
the PP over the PE.  Read the article if you are interested in why this
type of cap is self healing, I found it to be quite fascinating.  Easy
reading too.  I always wanted to know about the self healing properties,
now I do, how about you. :-) Fascinating

>
> The perfect loss-less dielectric would be a perfect vacuum, but that's
> cumbersome to deal with.
>
> Regards, Gary Lau
> Waltham, MA USA
>

Learning for as long as I can with the help of others,
Bill Parn