Re: Polyethylene and RF Chokes

To: tesla-at-pupman-dot-com
Subject: Re: Polyethylene and RF Chokes
From: "Bunnykiller" <bigfoo39-at-telocity-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Wed, 29 Mar 2000 06:50:07 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Tesla List wrote:
> 
> Original Poster: "Ryan Ries" <spud-at-wf-dot-net>
> 
> Hey.  I've been trying desperately to make a working flat plate capacitor
> with polyethylene sheets and alluminum foil.  When I get it done, it
> measures .03番, but it just shorts out as soon as I apply any voltage to
> it.  But I am sure that the poly is too thin, as well as extremely
> inferior.  If someone has some really thick polyethylene left over (or
> heck, some HV caps at that) that they can sell or send, I would be much
> obliged. :-)
> 
> Also, I have been thinking about making RF chokes. (I am using no safety
> circuit at all right now and haven't blown anything yet, but I still feel I
> should start protecting my investment. :))  I saw the air-core chokes on
> the net that looked just like little secondaries.  If I build a couple of
> these, what values am I looking for, and what will do what?
> 
>         Thanks,
>                Ryan



hi Ryan...

are the corners of the plating rounded? and ... what is the total
thickness of the plastic between plates? 

where is the general spot of failure occuring?

are you using oil with the cap?

any air between the plastic sheeting and foil will result in corona and
that = hotspot and that = POOF 

when i was doing plate caps the main failure point was at the corners of
the plates and at points where air was trapped 

plus i was using 75 thou of plastic between plates and still had
failures 

everything has to be ultra clean ..  no dust no dirt and clean oil


Scot D