Re: Magnetic quenching.

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Sean and John,

The following, I think, may be a variation to your idea John.  Lets have a
double triggered magnetic quencing system.  Lets say the first trigger
occurs when the spark gap fires.  Maybe a current transformer of a sort can
provide the trigger.  This trigger fires a one shot that has its timing set
to finish by 1st primary notch (or 2nd if we choose).  The trailing edge of
the one shot then fires a second one shot that turns on a magnetic quencher
(electro magnet powered by a DC supply perhaps) for a certain period.  This
way, magnetic quenching can begin at 1st notch and end when its safe to not
reignite (inhibit time).  Certainly, there is no current flow at 1st notch,
but if any current were to flow during the inhibit time, the H field would
disrupt it (at least that's the idea).

Challenges are to design the magnetic quenching circuit that has adequate
response time and the shielding for the monostables.  If this could be
built, one could experiment with 1st, 2nd, or 3rd notch quenching.

Gerry R

 > Original poster: Sean Taylor <sstaylor-at-uiuc.edu>
 >
 > On Fri, 12 Mar 2004 21:33:06 -0700, Tesla list <tesla-at-pupman-dot-com> wrote:
 >
 > >Original poster: John <fireba8104-at-yahoo-dot-com> Hi,
 > >   I was thinking the same thing but with a complex controller. The idea
 > > is that a short burst of high current (large value cap?--include diodes
 > > to attempt to stop ringing) is supplied to a electro-magnet every half
 > > cycle in order to "trigger the gap".This idea stems from a former post
 > > where breakdown voltages were given, showing a lower breakdown voltage
 > > with magnetic flux applied. Also, if is not to complex,  a current
 > > detecting device could be used to tell when the first notch is reached,
 > > triggering another magnetic pulse to quench the gap. To sum it up a sync
 > > trigger and a event(first notch) trigger for a single electro-magnet.
 > >Feasible, with a lot of work or just random ramblings.
 > >Cheers,
 > >John
 >
 >
 > Just thought of something . . .  First, I was (and I'm sure many others)
 > are thinking the same type of thing - a reverse triggered gap kind of.
 > Trigger exactly when you want the quench to take place.  Problem is, if
you
 > try to quench on a zero current crossing with a magnet, you won't get
 > anywhere until the current reaches some higher value.  As someone already
 > pointed out, a magnetic quenched gap works by deflecting the arc by
 > "pushing on the moving electrons - F = qVxB.  Problem is, for there to be
 > an velocity, there has to be current flow - so at a zero current crossing,
 > there is no force on the plasma channel.  Honestly, I don't see what the
 > advantage is (performance-wise) of a magnetic quenched gap vs. air blown.
 > Seems like the air blown gap would help everything - disperse ions, make
 > the arc path longer to help quenching, and cool the terminals.
 >
 > Sean Taylor
 > Urbana, IL
 >
 >
 >