Re: Another question

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Creeping sparks is the general term.  It's a well known phenomenon, and why
HV insulators have ridges, grooves, and corrugations.

There are two basic forms, depending on whether the spark is just along a
surface that is otherwise in free space, or whether the spark is along the
surface of a dielectric backed by some conducting surface (as, say PC board
with copper on just one side, or, more relevant to tesla coiling, a glass
bottle immersed in a conducting fluid)
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, December 26, 2001 9:56 AM
Subject: Re: Another question


> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Hollmike-at-aol-dot-com>
>
> I remember reading something about the phenomenon that abrupt change in
> dielectric constant, such as glass to air, can cause arcs to travel along
the
> interface much  easier than through either of the mediums them selves.
Don't
> know that there is a name to this phenomenon, but I watched a
demonstration of
> this at the Tesla museum as well.
> Mike
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> > I, too, have noticed that the arcs appearing along surfaces (such as the
> > outside of my salt water capacitors) are much longer than regular arcs
> > through the air.  A six inch surface arc could often be produced by the
> > same amount of voltage needed to throw a 1/2 inch spark in the air.
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