Modeling a magnifier
From: Robert W. Stephens [SMTP:rwstephens-at-headwaters-dot-com]
Sent: Tuesday, February 24, 1998 8:47 PM
To: Tesla List
Subject: Re: Modeling a magnifier
> To: "'Tesla List'" <tesla-at-pupman-dot-com>
> Subject: Modeling a magnifier
> Date: Sun, 22 Feb 1998 23:49:08 -0600
> From: Tesla List <tesla-at-pupman-dot-com>
> From: Greg Leyh [SMTP:lod-at-pacbell-dot-net]
> Sent: Sunday, February 22, 1998 4:17 AM
> To: Tesla List
> Subject: Re: Modeling a magnifier
> Robert W. Stephens wrote:
> > Maybe the unwashed masses representing the classical croud among us should
> > try rotary gaps that quench in tens of microseconds rather than the hundreds of
> > microseconds which is normal on most of our classical coils.
> > Certainly the multi-swept gaps of the maggys perform the
> > function of putting out the fire quickly by virtue of increasing the
> > approach and departure velocities of the electrodes greatly over
> > simpler 2 or 4 gap rotary designs.
> I haven't seen much mention on the List regarding
> the design and performance of multiple-swept gaps;
> usually its all about 2-gap rotaries in series with
> an array of static quench gaps.
> Realistically, most rotary gap systems have actual
> mechanical dwell times of many hundreds of usec's,
> if you consider the edge speeds, electrode widths,
> and the distance the electrodes must travel before
> the arc can be broken. There is little chance that
> _any combination_ of rotary and static gaps could
> quench in tens of usec's strictly _by themselves_;
> that is without a big arc hanging off the top of
> the output coil, stealing away most of the energy
> before it can bounce back to the primary.
> Even the finest and best thought out rotary/static
> gap combinations will ring for hundreds of usec's
> _if_ the toroid is large enough to prevent breakout.
I agree. Keep the secondary from breaking away by making
a large ROC topload and forget about quenching in your gap system.
I've got very good videotape footage of just such an occurance with
my own largest coil system. Malcolm Watts has referred to this exact
footage in this phenomenon context before.
I just posted further notes on this subject under separate cover
which deal with the rotary break contacts spewing metal ions because
they are being operated at incandescent surface temperatures. I
suspect this happens quite often during the learning curve/transition towards
higher power operation amongst many who attempt it.
One thing I can dfinitely say in this respect based on personal
experience as a helpfull hint is, "Do not employ stainless steel bolts as contacts
in your higher power rotary gap systems!"
Robert W. Stephens
Lindsay Scientific Co.
RR1 Shelburne, ON Canada L0N-1S5
Tel: 1-519-925-1771 Fax:
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