Re: Triggered gap questions

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

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Hi Ted,

Since you're running at relatively low power and using lots of air cooling,
I would guess that you should have excellent electrode life. Tungsten is
pretty tough stuff as long as you don't overheat it. I would expect that
they should behave similarly (wear-wise) as similar sized stationary
tungsten electrodes in a rotary spark gap operated at the same power
levels...

Good luck!

-- Bert -- 
-- 
Bert Hickman
Stoneridge Engineering
Email:    bert.hickman-at-aquila-dot-net
Web Site: http://www.teslamania-dot-com

Tesla list wrote:
> 
> Original poster: "Ted Rosenberg by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <Ted.Rosenberg-at-radioshack-dot-com>
> 
> Bert: As you might be aware by now, I am on the verge of building and
> installing a t-gap in my 900W coil. I have 1/8" diameter tungsten welding
> rods. They will be held in robust brass posts. Above the T will be a 250 cfm
> muffin fan pointed downwards and maybe an inch above the T.
> I will try to shape the trigger rod to a reasonable point tonight or
> tomorrow. I have a carbide and a diamond wheel which should do it.
> 
> Do you believe that I will be replacing the trigger rod often?
> Guesses at this point are permitted  :))
> Thanks
> 
> Ted
> (guinea pig for this project)
> 
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, August 01, 2001 10:48 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Triggered gap questions
> 
> Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <bert.hickman-at-aquila-dot-net>
> 
> Marc, all,
> 
> Once the trigger pulse fires the main gap, the main discharge will flow
> from one of the main electrodes, through the trigger electrode, to the
> other main electrode. The trigger electrode must be robust enough to
> withstand these high current discharges even though there's actually no
> high current flowing into or out of the trigger electrode. Erosion of the
> relatively small trigger electrode in trigatrons is a wearout mechanism.
> Because of high rep rates (120 PPS or possibly more with more sophisticated
> triggering circuitry in a DC system), I'd recommend using fairly robust
> trigger electrodes and substantial air flow to prevent the trigger
> electrode from overheating or excessively eroding...
> 
> Safe triggerin' to you!
> 
> -- Bert --
> --
> Bert Hickman
> Stoneridge Engineering
> Email:    bert.hickman-at-aquila-dot-net
> Web Site: http://www.teslamania-dot-com
> 
> Tesla list wrote:
> >
> > Original poster: "Metlicka Marc by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
> >
> > mike,
> > this is the nice thing about the whole triggered gap situation, "design
> > is WIDE open".
> > one thing though, the primary tank energy doesn't go THROUGH the trigger
> > electrode "per say", it tends to jump to it and then across to the other
> > main electrode. maybe it does actually go through it, i don't know? i
> > will have to listen to comments by those that are more knowledgeable
> > because i was "AMAZED" it worked great the first attempt?
> > the
> >
> > Tesla list wrote:
> > >
> > > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <Hollmike-at-aol-dot-com>
> > >
> > > Ok,  Here's a question for the triggered gap gurus:
> > >     I have been reading this thread with much interest.  It sounds like
> a
> > > great alternative to the SRSG!    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.
> > >    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).
> 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.
> > >  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?
> > > Mike
> > >
> > >