Re: what are creepage discs?

["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>

Those aren't corona rings, which are typically a set of conducting rings
spaced along an insulating column used to make the electric field more even.
The rings effectively form a series of capacitors, which form a voltage
divider to control the overall voltage distribution and to "swamp" any small
variations due to surface imperfections, etc.  You see them several places:
on HV (>1 MV) supplies (voltage multipliers, Van de Graaff generators,
etc.), and on the terminations of EHV insulator strings  (500 kV and up).
The purpose of the corona ring in the latter case is to make the effective
diameter of the conductor big enough that corona doesn't form.  In fact, in
general, corona rings are there to prevent corona, not create it.


On an insulator, you have ribs and rings to increase the creepage distance.
Creepage distance is the distance along the surface between the two
electrodes.  Typically, you want the creepage distance more than 3 times the
free air distance, although, for some devices and configurations (i.e. HV
"hocky puck" rectifiers), you can get by with less.  The usual. post
insulator or string insulator you see on a MV or  HV transmission line
typically has a very long creepage distance, because the insulators are
operating out in the dirt, muck, and fog.


> Original poster: "rheidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<rheidlebaugh-at-zialink-dot-com>
>
> look at a ceramic insulator, it has a series of carona rings to stop
racing
> arcs from running along the surface.I cut plastic rings with a hole saw or
> fly cutter and bond them to my secondary with fiber-glass resin so I can
use
> max coupling to get max power out.
>    Robert  H
>
> > From: "Tesla list" <tesla-at-pupman-dot-com>
> > Date: Mon, 31 Dec 2001 07:36:38 -0700
> > To: tesla-at-pupman-dot-com
> > Subject: what are creepage discs?
> > Original poster: > > <RQBauzon-at-aol-dot-com>
> >
> > ive heard someone was able to increase coupling and stop "racing sparks"
with
> > "creepage disks". ive seen pictures, and they look really interesting.
what
> > exactly are they?