From: FutureT@aol.com
Date: Sat, 11 May 2002 09:01:05 EDT
Subject: Re: [TSSP] Secondary voltage stress factor
--part1_12e.1132b2e4.2a0e7011_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 5/10/02 2:41:46 AM Eastern Daylight Time, paul@abelian.demon.co.uk writes: > > the bottom 2" of the coil burned up in places from racing > > sparks. > > With or without that extra 1/4" of secondary winding, the > coupling is still pretty 'smooth'. Why should the bottom of > the coil be clobbered like this? The most stressed part of > the coil occurs quite a bit higher up. Paul, all, In a prior similar coil, which was about 4 inches taller, I applied a lot more power, and got 56" to 63" sparks. Under these conditions, racing sparks did occur higher up, near the middle of the secondary. Racing sparks also occured near the bottom. The coupling was even looser, and the primary didn't come as close to the secondary. A larger 6" x 26" toroid was used. > > I'll throw another suggestion into the pot. At some high > frequency the primary will be in half-wave resonance, grounded > at both ends. Perhaps this or similar resonance is excited by > the primary arc and couples HF energy into the part of the > secondary close to the primary. > > Q: Do racing arcs ever occur on the third coil of a base-driven > magnifier? Yes, they do. Cheers, John > > -- > Paul Nicholson > -- > --part1_12e.1132b2e4.2a0e7011_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 5/10/02 2:41:46 AM Eastern Daylight Time, paul@abelian.demon.co.uk writes:
> the bottom 2" of the coil burned up in places from racing
> sparks.
With or without that extra 1/4" of secondary winding, the
coupling is still pretty 'smooth'. Why should the bottom of
the coil be clobbered like this? The most stressed part of
the coil occurs quite a bit higher up.
Paul, all,
In a prior similar coil, which was about 4 inches taller, I applied
a lot more power, and got 56" to 63" sparks. Under these
conditions, racing sparks did occur higher up, near the middle
of the secondary. Racing sparks also occured near the bottom.
The coupling was even looser, and the primary
didn't come as close to the secondary. A larger 6" x 26" toroid
was used.
I'll throw another suggestion into the pot. At some high
frequency the primary will be in half-wave resonance, grounded
at both ends. Perhaps this or similar resonance is excited by
the primary arc and couples HF energy into the part of the
secondary close to the primary.
Q: Do racing arcs ever occur on the third coil of a base-driven
magnifier?
Yes, they do.
Cheers,
John
--
Paul Nicholson
--
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Maintainer Paul Nicholson, paul@abelian.demon.co.uk.