[Prev][Next][Index][Thread]

Re: Laser Triggered Spark Gap

Hi Steve, 
    The heat will require special engineering.  I will be designing such a
gap this next year for a new project.  Instinctively I would begin
considering a gap that spreads the heat out such as the rail or annular
geometries.  Massive heat sinking coupled with big fans.  If you pressurize
the gap it becomes more efficient and requires less heat removal.  Hydrogen
atmosphere at a few hundred PSIG would be nice.  Elkonite electrodes on
plates with internal and external heat sinks to cool the Hydrogen gas.  4
by 4 box to contain the switch in case it goes off.

    By the way a triggered gap is more efficient because the formation
energy is supplied externally to the main energy store.  This would add a
little Q to the primary circuit.  The electronically triggered crowbar
switch that I designed and built worked very well the first time.  I found
out something very interesting at the same time.  When the switch broke it
shorted the load circuit, trapping current in it.  The Q was incredible
despite the 2 centimeters of arc in the load circuit.  I attribute this to
the low impedance of the gap due to the external ionization source. It is a
very stiff trigger (200 kV 5 stage Marx, 320 Joules).

  
-----Original Message-----
From: Tesla List +ADw-tesla+AEA-pupman-dot-com+AD4-
To: tesla+AEA-pupman-dot-com +ADw-tesla+AEA-pupman-dot-com+AD4-
Date: Thursday, November 05, 1998 9:40 AM
Subject: Re: Laser Triggered Spark Gap


Original Poster: +ACI-Steve Young+ACI- +ADw-youngs+AEA-konnections-dot-com+AD4- 



Barry and all,

Thanks for the valuable information.  I can appreciate how high pressure
triggered spark gaps (TSG) will perform much better.  But if the TSG is
firing hundreds of times a second, how do you get rid of the heat?  One
would have to water cool the pressurized container, and have a continuous
flow of high pressure gas to exhaust the heat and vaporized metal, I would
think.  I suppose an air compressor could be used.  (And the pressurized
TSG exhaust might be useful for light welding??)  

As far as a wider spaced gap being more lossy, I can appreciate that also. 
But is the loss between a 0.8 inch vs 0.4 inch total gap length, for
example, really that significant?

Imagine a Richard Quick style gap.  Suppose it works great with 6 gaps but
can't fire with 7 gaps, all equally spaced.  If the 7th gap is a TSG, the
extra loss introduced by that one more gap shouldn't by very significant. 
Am I missing something?

--Steve