Re: three phase coiling

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

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, January 18, 2004 5:04 PM
Subject: Re: three phase coiling


 > Original poster: Greg Leyh <lod-at-pacbell-dot-net>
 >
 > Solid-state primary switching might be the best way to get the timing
 > resolution you require for accurate 3-phase RF control.  I'll have a
better
 > idea within a few weeks what degree of control such a 'phasing' knob has
on
 > the output arcs of a twin coil.  The phasing control for the ALF prototype
 > will have a resolution of about 200nS, on a 16uS period Fo.
 >
 > -GL
 >

But... I haven't seen many (inexpensive) solid state primary switches that
can take the kilovolts at kiloamps kind of thing that a spark gap does so
nicely.  However, maybe triggered spark gaps might be the ticket.


 >
 > >Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 > >I've been running some interesting simulations, in respect of having 3
 > >basically identical (but slightly different) coils running
simultaneously,
 > >near each other, to see if you could get triangular or Wye sparks.
 > >
 > >The first cut is to try and force the coils to run 120 deg out of phase
with
 > >each other (RF phase, not AC charging).  I worked out some LC networks
and
 > >such that can do this (you basically create something that looks like a
 > >phase shift oscillator network), but I suspect that as the sparks grow,
the
 > >loading will change the frequency enough to perturb the situation.
 > >
 > >[snip]
 > >
 > >I suspect that any sort of spark gap system will have enough jitter in it
 > >that precisely synchronized firing (we're talking tenths of microseconds,
 > >here) is unlikely to occur.  In fact, one can help things along a bit by
 > >providing some loose coupling with a phase shift between the primaries,
and
 > >running a triggered/rotary gap  on one primary and static gaps on the
 > >others.  As the first coil fires, the voltage change in it will raise or
 > >lower the voltage on the other coil (depending on if it's leading or
lagging
 > >coupling), and cause it to fire a bit early or late, making the RF out of
 > >phase.
 > >
 > >Comments?
 >
 >
 >
 >
 >