Subject: Setting Up
From: richard.quick-at-slug-dot-org (Richard Quick)
Date: Sun, 25 Feb 1996 05:09:00 GMT
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Today (Sunday) I pulled all of my heavy Tesla Equipment out of
storage and loaded it all into the garage. It took six trips with
my brother's Explorer to get it all.
Saturday night my wife and I went went over to my brother's house
for dinner. I had some light coiling stuff in his basement (and
some in mine), but most of the heavy stuff was in a commercial
storage locker. But I caught the urge to smell some ozone.
I grabbed a couple of homemade capacitors, small 15 amp power
cabinet, a 5" diam coil wound on thin wall acrylic, 12x3 toroid,
an ancient cylinder static, copper pipe primary with 60 feet of
3/8" diam. refrigerator tubing wound on a wooden form in an
inverse conical section (saucer type) primary with about a 30
degree inclination and a 12 kv 60 ma neon.
There is no RF ground in my brother's house. I made a
counterpoise system using some scrap Al flashing from an old
capacitor project, two galvinized steel trash cans, and a
stripped car chassis.
Setting the coil up from here was pretty easy. The coil tuned all
the way out on the primary with ~.01 uF capacitance in the tank.
Once I had the gap working smoothly (after the bit of cleaning
from having been stored dirty, add oxidation and lots of dust)
I was getting an easy 24 inches of good hot spark.
A good point to note: you can almost always obtain decent
performance from a coil system if you have more transformer
than required for a decent match. For instance with the above
power supply, the idea tank circuit capacitor value should have
been about .0132 uF compared to my ~.01 uF. If transformer is
large enough to supply the capacitor with surplus, things are
just fine. The other way around does not work so well.
About this time my gap shorted, burned out, and ended up in the
"scrap" junk box. I have seen this failure before on old cylinder
static gaps. What happens is that copper is sublimed from the
electrodes and is deposited on the PVC plastic ring above the
electrodes. Little brown "plumes" of sublimed copper are an
indication of gap age. It also shows that the muffin fan is
really doing it's job of removing some hot ions and helping cool
things down a bit. After many hours of use the copper build up on
the plastic is heavy enough to form a conductive bridge between
the tops of the copper pipe electrodes. The arc jumps around the
plastic, carbonizing the plastic and ruining the gap.
To prevent this I have found that a good cleaning up with a bead
blaster not only removes accumulated slag from the electrode
faces, but also removes sublimed copper from the outer plastic
ring. Cylinder static gaps using larger diameter copper pipe
sections mounted in a larger plastic pipe do not have this
problem: the actual gap surface is too far away from the plastic
housing to allow for much sublimation.
Anyway, I grabbed another gap, (I cleaned this one up a little
better), and swapped in two 15kv 30ma neons wired in parallel for
more power and a better transformer/capacitor match. About this
time we were pulling off nearly 3 feet of spark.
A wonderful time was had by all, and it gave me the incentive I
needed to put in a full day of back-breaking work moving pole
pigs, power cabinets, variacs, arc welder, a couple of dozen
neons and stripped cores, homemade pulse capacitors (one full
greasy load), pfc capacitors, toroids, filter boards, spark gap
assemblies, boxes of cable and connectors, spools of magnet wire,
coils, coils, and more coils... You get the idea.
All piled up in one place it looks like a pretty impressive
collection. Give me a few weeks and I should have some barn
burners up and firing.
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12