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First big magnifier run
Wild Bill Emery and I finally set up our large magnifier out in my driveway
Saturday night and fired her up. We started with a 40 inch by 5 inch toroid
on top of a 4 inch by 13.75 inch resonator coil (30 gauge). We video taped
the runs, and then measured honest 90 inch strikes to the house and garage
door frame. After running it, we found that I had failed to lock down one
of the stationary electrodes on the rotary gap, and it had opened up to over
1/2 inch gap, and it still worked! We will redo the gap on our next series
of runs.
We first experimented with using the secondary in the driver as a
conventional Tesla coil. It is only about 180 turns of 10 gauge wire on a
16 inch diameter pvc pipe, so inductance is not much. We tried the 40x5
toroid as well as the 60x8 inch top, and all we ever got was sparks racing
down the secondary - and this was with the coupling about as low as we could
go without raising the secondary up (it weighs 107 pounds, so raising it up
a foot or so is no small task.) We finally gave up on trying to use it as a
conventional coil, and decided to use it as a driver, as it was so designed.
What was absolutely incredible during this "conventional coil" attempt is
that we had some extremely hot, violent arcs from the toroid down to the
primary. Sometimes, but not every time when this happened, we got 23 inch
flashovers from the bottom of the primary to the concrete driveway! We have
the entire coil assembly sitting on top of 22 inch tall porcelain
insulators, and the primary arced all the way to the concrete, jumping
AROUND a 3/8 inch copper line run straight to my water main. I am still
stunned at seeing this. I repeatedly watched this frame-by-frame on video,
and it is weird. Apparently there is ground, and then there is ground. My
main ground is 3/8 copper tubing screwed directly to a brass water faucet on
the front of the house. The faucet is connected to a copper water line
which immediately runs 30 feet under the yard to the water meter, and from
there to the water main under the street. I dug up a section of the line
from the meter to the house to make sure it was copper before I ever used it
as my coil ground. I figure 30 feet of buried copper line connected to a
buried water main is a damn good ground, so why would a strike to my
concrete driveway just ignore a copper ground line connected to this superb
ground? The arc had to bypass the best ground I can make and instead opted
for some crummy concrete. I know the copper water pipe ground is adequate,
as my coil is performing quite well. Those 23 inch strikes to the driveway
passed within one inch of my ground and absolutely ignored it.
Anyway, we will put the much larger top on the resonator coil next time and
we should get much longer sparks. Our goal is to go beyond 10 feet, and
with 7.5 feet on our first run (and this was using our first "best guess"
primary tap setting!), I think we are well on our way there.
I shot about half a roll of 35 mm film of the coil's driver construction,
and I'll get this developed and scanned next week, I'll pass it on to Chip.
I did not shoot any film of the coil running yet, only video. I'll take
some stills the next time we run it. We're going to wind two new resonator
coils, one will be a 12 inch diameter pvc pipe wound with 18 ga wire, and
one will be a monster 16 inch diameter coil wound with 10 gauge. This is
getting to be a lot of fun!
We're running a 20,200 volt transformer, which is very loud on the rotary
gap. I had several neighbors standing in their yards watching the show. I
wish I had a large building to run this coil in, but unfortunately my yard
will have to do. I think I'm moving it all to the back patio for my next
test run to reduce the neighborhood interest. I figured on my first run if
I even got it to break out of the toroid, I'd be doing good. I didn't expect
90 inch sparks and didn't want to generate quite so much neighborhood interest.
Bert Pool
nikki-at-fastlane-dot-net