Re: Triggered gap questions

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

The Deutsches Museum marx doesn't use a UV laser to trigger (unless they've
changed it since August 99, when I last saw it).  It's a fairly standard
Marx using a stack of sphere gaps arranged in a line and a trigatron on the
bottom gap for control.  The spheres are all arranged on a common insulating
rod that can be pivoted to set the gap, and hence the trigger voltage.  They
can also be swung to close all the gaps, providing a form of safety shunt.
Joachim Kronjaeger has the schematic diagram on his web site.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, July 26, 2001 7:25 PM
Subject: Re: Triggered gap questions


> Original poster: "Jason by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jasonp-at-btinternet-dot-com>
>
> Mike,
>
> > One thing I read is that the primary
> > current passes 'through' the trigger electrode.  My question is, could
the
> > trigger electrode be positioned slightly out of alignment with the
primary
> > gap electrodes so the triggered arc would have to take a slightly 'bent'
> > path?  This, if so, would seem to me to help alleviate heating and/or
> > corrosion of the trigger electrode.
> Not really - If you have a kind of setup as in a safety gap with the
central
> electrode as a trigger, thenyou will still get burning/corrosion/whatever/
> The only way to not get corrosion on your trigger electrode, is not use
one.
> (Use a UV laser to trigger it, as they do in the deutches museum in munich
> for their marx) The best way of minimising wear is to use tungsten for the
> trigger 'ode.
>
> >    It would seem that the trigger electrode could be made into a sharp
> point
> > and cause the ionization of the space between the gap electrodes to
> provide
> > the conductive channel to form more easily and not actually have the
> primary
> > current contact the trigger electrode at all(or very little anyway).
> Good idea in theory - However in practice the electricity will always take
> the path of least resistance, i.e. along the ionised air (which will be
> attracted to the gap electrodes by the high gap potential) and through the
> needle (which WOULD burn up).
>
> > If the
> > trigger electrode were positioned from below the primary gap electrodes,
> the
> > heat might also help 'move' the arc away from the trigger electrode.
> Possibly, although over the time that we are talking about (a few uS)
there
> wouldnt really be enough time to create a Jacobs Ladder effect.
>
> >  The first objection to this idea, I imagine, is that might argue that
> this
> > would effectively make the gap too wide and kill a NST, but if one
placed
> > another gap or two in series, the triggered gap could have a large
> percentage
> > length change, but the overall gap length would not change by much.
> Having
> > the series gaps would also seem to aid quenching as well.
> > Comments?
> The positioning of the trigger 'ode below the gap 'odes would not cause
> misfiring unless the gap space was incorrectly set.
>
> My thoughts on triggered gaps - The best way to make a triggered gap is to
> use the multi segment SG design, and place the trigger across the first
gap
> like this:
>
> OOOOO|O
>
> so that once the trigger fires, the volts/gap increases (less inactive
gaps
> = more volts/gap) thus making the rest of the gaps fire in sequence, as
> happens in a marx generator. This is in my opinion the best method.
>
> Good Luck!
> Jason
>
> > Mike
> >
> >
> >
> >
>
>
>