RE: Some tests with a 2.25" coil (Followup, Solved?)

To: tesla-at-pupman-dot-com
Subject: RE: Some tests with a 2.25" coil (Followup, Solved?)
From: "Coiler" <mycroft-at-access1-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Fri, 23 Oct 1998 16:30:47 -0600
Approved: terryf-at-verinet-dot-com
Below, you'll find the original message. I did some further testing tonight.
The setup was exactly the same as described below, with one exception.
I set up a 4.25 Box fan about 1 foot away from the safety gap of my
capacitor. This resulted in the most gentle of breezes blowing across it.
Fired up the coil, and ran for almost 5 minutes. During this time
the cap gap fired twice.
Checking after the run:
1) The main gap was too hot to touch [ I had to get the fan to run the test
from
   somewhere]
2) Primary coil was warm to the touch
3) Likewise the tank wiring.

So I think I finally figured out what was going on. The new enclosure for my
cap
has about 5" of headroom. But 2.5" of that is actually a trap for ionized
gas.
Apparently the HV RF present on the gap was producing enough ions to
eventually
cause breakdown.

I'll do a little more testing just to make sure, but I thought I'd fill you
all
in. Thanks for the help along the way.


[ For those that wonder, the gap is formed of 1/4-20 bolts, with acorn
  at the business end.]


>
> > As some of you know, I have been fighting a few battles with my system -
> > one of which is protecting my door opener :)
> >
> > The other one has been working with my *expletive* capactitor
> safety gap.
> > Since I could not run as high power, I grabbed one of my old coils
> > to stick in the primary as a load.. it happened to be my 2.25 x 12"
> > coil, wound with 28AWG wire. I threw my old 3"x10" toroid on there
> > mostly to get to where I could at least use a few turns of my primary.
> > The little coil looked lost in there :) [ 8.5" inner turn for my 6.5"
> > coil]
> >
> > Specs for test:
> > 2.25x12 Coil, with 3x10 Topload.
> > Main Gap 0.175
> > Cap Gap 0.470
> > Power source: 14.4 Pig, with input voltage limited to 100V (12KV output)
> >                1100VA limiting in place.
> >
> > Doing short runs (under 5 seconds) things were fine. Produced
> anywhere from
> > 2-6 14" streamers. After I got things tuned up I let the system
> run for a
> > bit
> > (about 20 seconds) when my cap safety gap started to go nuts. I
> checked my
> > main
> > gap, and the pipes were *HOT* (my kids had broken my fan plenum
> - so the air
> > was not ducted to my RQ gap.) So I got curious. I let it cool down, and
> > fired
> > up the coil.. things ran fine for about 30 seconds... then *bang* the
> > safety gap fires.. Again, the gap is hot.
> >
> > I am speculating that the poor quenching caused by the overheated gap is
> > playing
> > a role in the problems I am seeing with my safety gap, can any of you
> > give some additional information in support of or against this idea?
> > The only other possiblity (which I have not been able to test
> yet, wife made
> > me shut down because of the noise) is that the new enclosure I
> built for my
> > caps is harboring ionized air from the cap gap.. and that this
> eventually
> > leads
> > to the breakdown.
> >
> > Michael Baumann
> > Coiler, Homebrewer, Nerd. mycroft-at-access1-dot-net
> >
> >
> >
>