Re: Bigger top = bigger sparks

From: 	Chuck Curran[SMTP:ccurran-at-execpc-dot-com]
Sent: 	Monday, June 30, 1997 8:30 PM
To: 	Tesla List
Subject: 	Re: Bigger top = bigger sparks

Tesla List wrote:
> From:   Bert Pool[SMTP:bertpool-at-flash-dot-net]
> Sent:   Saturday, June 28, 1997 8:10 PM
> To:     Tesla List
> Subject:        Bigger top = bigger sparks
> We just had an excellent Tesla magnifier run, with measured sparks 11
> feet in length.  We were running a 62 inch diameter toroid with an 8
> inch cross section stacked on top of two 36 by 8 inch toroids.  The
> first time we ran the big top, we were out of tune, and some violent
> interturn sparking shorted out and effectively destroyed our two
> layer extra coil.  We added one turn on the primary and replaced the
> extra coil with our single layer unit.  This is the first time we've
> had sufficient power and tune to use the large toroid, and it  was
> nice to get it to run.  We shot some excellent video, and even had
> had one guy with a stereo camera positioned on top of a steet metal
> roof with 10 and 11 foot sparks hitting the edge of  the roof about
> two to three feet from the cameraman's feet.  I have to give Jerry
> David Gore credit, he held his ground, so to speak.  His camera and
> tripod were picking up so much EM field that he couldn't touch his
> camera, so we isolated him with a sheet of plexiglass and he was able
> to take some shots - we hope they will be good ones.  The video
> from the roof looking down into the big sparks was great.  Our
> longest run ever was 4 and 1/2 minutes exactly; and that is a very
> long run for a coil.  If you have anything weak in the system, an
> extended run will show it up.  We checked our stationary electrodes
> on the rotary gap - they got too hot to touch, but not hot enough to
> damage the gap frame.  We also lost a welder when we tried to
> parallel it with our first welder.  There were instant balls of
> molten metal splashing out of the inside of the welder - not a good
> sign, so we never got to push the extra power we wanted.  Max kva
> measured at the wall was about 12 kva.  Oh yeah, we had to replace
> the 3 inch diameter corona ring on top of the secondary with a 7 inch
> cross section toroid 30 inches in diameter.  We needed some field
> shaping at the top of the secondary, and we also found we had to
> raise this toroid about an inch to prevent strikes from the
> secondary to the primary.  Our flat aluminum flashing transmission
> line has been stiffened by stapling some 8 foot long wood strips 1/2
> inch by 1/2 inch to the back side; we did this to prevent the
> transmission line from "flagging" when breezes blow through the yard.
> Bert Pool
> bertpool-at-flash-dot-net

Sounds like you really had things going well!  4 1/2 minutes of run time
is pretty respectable for a new system still being developed.  I have
kept my two coil system to about 2 minutes and was happy that nothing
got too upset this last Friday. The toroid stack must look pretty neat
too--do the cars slow down when you are just setting up, trying to
figure out what you're doing?  Your comment about the transmission line
flapping in the breeze caught my attention.  I have been wondering what
would happen if all of us who run our coils outside in the wind, could
one day take them inside and not let the wind disrupt our "ionized
air".  I bet your 11' spark would stretch out some more, based on
comments heard before.  Hope you are able to post a photo of the system
when time permits, too bad about the damaged/dead welder.

I tried taking a time exposure Friday night of my coil running.  I had
an older Konica camera that was funtional last year but this year it
gave up the ghost.  Next I got two really old Leica cameras from my
Uncle's estate when he passed away and I tried one of them, knowing that
a 1939 vintage camera would be 100% mechanical--it doesn't work yet
either.  Last resort was my new Minolta, which I took one shot with and
then it did some odd things.  It's still O.K.--I knew I should not try
it so close to the coil, but I really wanted to get a photo to post! 
Well, I'll get the one developed and see if it turned out or not.  If
not, I'll keep trying.  Sunday my wife asked me what happened to the
Flowering Crab tree.  A whole bunch of leaves were dead--wilted and
brown where the coil had hit them during the run.  Neighbors from six
houses down the road came by to watch that big bug zapper run, as they
called it.

Chuck Curran