Re: Terry, post this for me

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

Original poster: "Justin Hays by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi All.

Patrick: All of your "common sense" ponderings are correct with
regard to the short sparks. You've basically got everything right.

Fixes:

1. Wind that off-axis inductor. Get some bare copper (doesn't matter
what size, but make it 14 gauge or larger) and wind it on 4" PVC
pipe. Wind A LOT of it on, like, 50 feet or so. The off axis inductor
gives the effect of adding primary coil turns.....the more turns the
better in your case, to lower your driving frequency.

2. As a last resort only, keep adding bottles. Each bottle you add
robs you of input power. Adding primary turns doesn't take away much
power at ALL compared to adding bottles. Anyhow, your secondary is
tall, and wound with relatively small wire for a 4" coil, that means
its frequency is very low, which makes things bigger (requires bigger
primary, or more tank capacitance). 

3. You've got to find another way to do tank capacitors. Saltwater
capacitors don't work very good *at all* below one kVA or so. I know
you know that, but, 10 or 12 inches might be all you can get with
them and your 12kV 30mA xfmr. That bad.

OH --- replace your toroid with something MUCH smaller, like, a
doorknob. See what happens. If sparks get longer, tweak on everything
else (add caps and primary turns) with the small toroid. THEN add a
bigger top when it's in tune, and fool with it from there.

The Geek Group sells some excellent capacitors, they are .15uF -at-
1600VDC. Truly wonderful devices for an MMC capacitor, a friend of
mine Mark Stolz tried them on his 2" secondary. I watched 4 foot arcs
spew out of it running 3kVA input. Theres no way to do that other
than to have a good setup and a good tank cap. Go MMC, or, you can do
the "stacked poly" thing. That makes a good cap also, just design it
for 40 or 50kVDC of insulation and you'll be in good shape. Use
polyethylene sheet for the insulator.

Easiest thing to do other than using a smaller top, is to wind that
off-axis inductor. Put it in series with your primary coil, and start
tapping out turn by turn until you find a peak in performance. Where
it peaks, is the most you'll get until you get a better capacitor.
You'll be very pleased with it though, I'm sure. When you're tuned
you will KNOW it. Arcs get much longer, and straighter, with less
wispy little fingers everywhere and more long branching ones.

One more quick thing: 

I have cut a secondary in half before. It makes two coils that are
every bit as pretty as the first. And sparks are nearly twice as long
because you've arranged it into a twin coil......all you need is
another primary, and HALF the original tank capacitance (provided it
was in tune when you started!)

Big coils that are tall, don't make sparks nearly as long as that
same coil cut in half, and used as a twin. Twins are easier than most
people think.

Later,

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com






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