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>
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
> by Malcolm Watts in "Electronics World + Wireless World" dated March 95
> UK publication).
> I have read many references in this list about failure of capacitors due
> air bubbles. I am currently making a flat plate capacitor of 0.015uF.
> using Polystyrene Sheet (80 mil thick), and sticking aluminium foil to
> 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
> 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
> Viv Watts.
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 --