Re: Static Gap question.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com> 

Corona at 300 Volts? Is it not visible to the human eye? Or is it just very
small amounts( I know that all surfaces produce corona at any voltage).

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, February 11, 2004 1:13 PM
Subject: Re: Static Gap question.


Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>

Tesla list wrote:

  > Original poster: "Luke" <Bluu-at-cox-dot-net>

  > Question 1.
  > If the gap is cooled off sufficiently and the gap is quenched well say by
  > large amounts of air is there any other benefit to using a larger surface
  > area for the spark gap?

For a gap of reasonable dimensions you usually require a
large surface and some forced cooling. Spark gaps get really hot.

  > And question 2.
  > The JavaTC program estimation of the arc distance in relation to
potential
  > is based on the surfaces of the spark gap being curved like as in large
  > dia. balls or pipes in parallel.
  > This assumes the distance between electrodes is not greater than the
  > diameter of the electrodes.

If the 30 kV/cm figure is used, the diameter of the electrodes shall be
much greater than their separation.
Two 1 cm balls separated by 1 cm break down at about 17 kV, if very
perfect and cold.

  > Would the same approximate distances be obtained for said voltage if flat
  > electrodes were used parallel to one another?  Say like two 1" dia. discs
  > separated by ½".  Would that have a breakdown voltage close to the
  > breakdown voltage of two 1" dia. copper pipes in parallel to one another?

Only if the edges are sufficiently rounded. With sharp edges, corona
there begins at about 300 V, and long sparks at about 10 kV/cm, or less
once the edges get hot.

Antonio Carlos M. de Queiroz





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