TSSP: List Archives

From: "Lau, Gary"
Date: Sat, 2 Jun 2001 09:24:51 -0500
Subject: Re: [TSSP] Racing arc clues

>First, I think we need to recognise that racing arcs are simply a case
>of the secondary breaking down before anything else. Then the advice we
>might give to cure a case could be one or more of the following,
>
> a) Reduce the drive power.  (Not what you really want to hear).
>
> b) Use a smaller toroid. (Its lower breakout potential will ensure
>    the topload breaks out before the secondary.)
>
> c) Add a breakout point to the toroid. (Again, ensuring that the
>    topload breaks out first).
>
> d) Reduce the coupling. (The topvolts still reaches much the same
>    ultimate peak value, just takes a little longer to get there, and
>    we have a smoother voltage gradient on the secondary).
>
> e) Arrange a strike ring or some other earthed fitting to act as a
>    'spark gap' limiter for voltage rise. (The toroid breaks out to
>    this object before the secondary breaks down.)
>
> f) Increase the BPS. (So that accumulation of streamer breakout from
>    the topload over successive bangs helps to keep the voltage down).
>
>Have I missed anything out?



Several coilers have reported that coupling and performance may be
increased beyond the point that the racing sparks would normally occur,
by installing several creepage disks along the length of the secondary.
See http://home.mmcable.com/surplus/newdevelopments.htm

The only down side I can see is that it permanently makes the secondary
much more fragile, bulky, and cumbersome to store.

Perhaps there is some kind of secondary coating that could be applied
that has a higher surface breakdown voltage than polyurethane (or magnet
wire enamel, whatever)?

Gary Lau
MA, USA


Maintainer Paul Nicholson, paul@abelian.demon.co.uk.