Re: air blown triggered gap

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

Original poster: "Metlicka Marc by way of Terry Fritz <twftesla-at-uswest-dot-net>" <mystuffs-at-orwell-dot-net>

hi gregory, all

Tesla list wrote:
> 
> Original poster: "Gregory Hunter by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <ghunter31014-at-yahoo-dot-com>
> 
> Hi Marc,
> 
> I studied your pictures.  Nice workmanship! I have a
> question.  Are the main gap electrodes axial with the
> acrylic tube? 

yes the main electrodes are axial to the airflow through the glass. the
air is being pulled from the leads end and then through the blower, the
leads and wire tie are blocking much of the volume at the moment, but i
need the tie or else the electrode and plates are sucked through. i do
need to cut the electrode mounting plates down because at higher powers
the arc hits the plate 2 out of 5 times, i think the air pulling across
it could be the issue here?
i haven't had any quenching problems so far, but the max i've pushed is
12kv-at-60ma. shad is working on high powered testing with his pig and has
had some quench problems in it, one thing i suggested (that was actually
suggested to me) is to try using a somewhat static gap with a center
electrode used as a trigger.
in setting the trigger electrode position between the main electrodes,
i've found the best placement is so the trigger arc jumps from one
electrode to the other instead of always contacting one. not sure why
this would be a better placement, but it is?
in initial firing of the air quenched triggered gap, i have found that
it takes a little less pulse width on the dimmer then without air,
haven't figured this out yet but i've only just begun.
now that i have the air quenched setup working to quench and cool the
electrodes, i will begin getting scope data of the system, i'm hoping to
get some "real time" data of pulse width of the trigger, primary
currents (thanks terry), break rates, and in building the air quenched
gap inside of the pyrex should allow some visual monitoring of the
triggered arc itself? i have four channels available and a data
acquisition card so i'm hopeful?

I'm asking because you mentioned
> quenching problems.  The gap might work better if the
> air blast was at a right angle to the main gap axis so
> the air could blow through it instead of around it.

i agree that the air blown directly across the arc will tend to quench
the arc better, but for this unit i was thinking that as long as the
triggered arc is hitting the far electrode, then the high speed air
stream would pull the arc away from the near electrode when the trigger
turns off. this does seam to be the case.
i may have access to a high speed camera on the weekends if i buy the
film, this is pricey, but i may take some high speed pics of the gap and
maybe some streamers?


> Did I see it wrong?

you've hit it right on the nose. as a side note, the streamers from a
12\30 nst and .012uf bucket cap on this coil are running about 26",
without the air quench the streamers are a little thicker and less
mobile, with the air quenching the streamers are thinner more branched
and more active. this could be a result of the dimmer having to be
turned down to a lower pulse width?
it does seem that some filtering could be used on the mains to the
triggered coil, many good suggestions are coming in for different setups
so i will be busy. haven't had any blown fuses or problems, but i want
to scope the mains to the trigger coil to look for spiking problems or
??

thanks to all that have given suggestions, keep them coming please.
marc m.

> 
> Greg
> http://hot-streamer-dot-com/greg
> 
> --- Tesla list <tesla-at-pupman-dot-com> wrote:
> > Original poster: "Metlicka Marc by way of Terry
> > Fritz <twftesla-at-uswest-dot-net>" <mystuffs-at-orwell-dot-net>
> >
> > hello all,
> > i have built an air blown (sucked?) triggered gap
> > unit to use in my
> > higher break rate experiments and on my pt system.
> > picks can be seen at
> >
> http://www.fortunecity-dot-com/meltingpot/syria/1210/id40.htm
> > i have much to get on this site so please bare with
> > me?
> > marc m.
> >
> >

note for all-- dataq -dot-com is offering nice little data acquisition card
starter kits for free if you put just the right info on the on-line
request form. these are nice little four channel units that connect to
the serial port, beautiful software and for fifteen dollars you can
unlock all four channels for storing data. the software will run at high
sample rates, but the card is limited.
all in all
well worth the effort of a look
i suggested them to shad and he got one, maybe he can comment?


> >
> 
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