Re: poly cap

Tesla List wrote:
> Original Poster: "Kevin Wahila" <knw2-at-lehigh.edu>
> What is the best poly thickness to be used in a rolled cap with a 9kV neon
> system?
> thanks
> kevin wahila


It depends to some extent on the thickness of the poly that you're using
and how "bulletproof" you want to make your cap. Thinner sheets of poly
actually have a higher breakdown voltage (in volts/mil). Also, it's
critical that you have at least 2 sheets of poly between plates to
prevent a single dielectric defect from destroying your cap. I'd
recommend using at least 50-60 mils of poly if you're using 25-30 mil
material. If you're using 6 mil poly or thinner, you could reduce this
to 35-50 mils. You can always go thicker... going thinner simply pushes
you closer to the edge of breakdown but saves on the initial cost and
size of the cap. 

In any case, it will be inmportant to remove as much entrapped air as
possible by either drawing a partial vacuum or by running the cap
vertically and using an extended break-in period at lower power levels.

Safe cappin' to yoi!

-- Bert --