Re: Bubbles

Subject:       Re: Bubbles
       Date:   Thu, 12 Jun 1997 06:27:36 -0700
       From:    Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization:   Stoneridge Engineering
         To:    Tesla List <tesla-at-pupman-dot-com>
 References:    1

Tesla List wrote:
> Subject:  Bubbles
>   Date:   Wed, 11 Jun 1997 23:30:44 +0100
>   From:  "V C Watts" <V.C.Watts-at-btinternet-dot-com>
>     To:  "Tesla List" <tesla-at-pupman-dot-com>
> I am currently building my first coil inspired by this list and an
> article
> by Malcolm Watts in "Electronics World + Wireless World" dated March 95
> (a
> UK publication).
> I have read many references in this list about failure of capacitors due
> to
> air bubbles.  I am currently making a flat plate capacitor of 0.015uF.
> I'm
> using Polystyrene Sheet (80 mil thick), and sticking aluminium foil to
> it
> with insulating varnish.
> Because I know I have air bubbles what can I
> expect the failure mode to be?  I expect the breakdown voltage to be
> about
> 40Kv so should be ok with by 10KV 50ma Neon transformer.
> Also are their any other coilers in the UK,  I don't see much UK
> correspondance?
> Viv Watts.


Welcome aboard!! 

Entrapped air in a capacitor will ionize when the cap is used in Tesla
Coil service. Ionization eventually destroys the capacitor dielectric
through a combination of localized heating and the highly reactive
chemical effects of the ozone and UV radiation. However, the 80 mil
thick dielectric should provide you with a degree of safety margin if
you're only planning to run it from a 10 KV source. Let us know how the
coil turns out, and good luck to you!!

-- Bert H --