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Re: Bottle Caps; First Firing
From: ghunter-at-mail.enterprise-dot-net[SMTP:ghunter-at-mail.enterprise-dot-net]
Sent: Friday, November 14, 1997 5:00 PM
To: Tesla List
Subject: Bottle Caps; First Firing
Just fired up the little 4.5" x 23" TC for the first time. Tuning
up was a pain. Took me an hour to find the sweet spot on the primary.
Sparks were only 6 to 8 inches. A bit disappointing. I can see
part of the problem right off. My foil-covered wine bottle caps
(5 caps for .0056uF total) glow with lavender corona. The loss must be
horrendous. I plan to paint them with melted parafin in an attempt
to suppress the corona.
I could see a bright corona halo coming from the top turn of the
secondary winding. It was blowing right through the thick, sloppy
coatings of gloss urethane. The top windings of my secondary are
going to get the hot wax treatment as well.
Another problem. My 5k, 50w series power resistors (one per
transformer leg) are getting hot as pistols. Obviously, they are
eating some power. I'm going to replace them with 100 turn chokes
wound on 1" x 5" cylindrical ferrite forms. This will reduce ohmic
loss while (hopefully) preventing raw RF from reaching my neon
secondary.
In frustration I opened the gaps up wide. The 15kv neon could just
barely fire them. Sparks increased to about 12" and the noise was
deafening. The safety gaps were firing like mad. Gave me the
creeps. I know this treatment is hard on both the neon and my vino
bottles. I put the gaps back to a sane setting. I'll pursue longer
sparks through incremental improvements in efficiency instead of
blowing up my neon & cracking glass. Sure was fun though. I wanna
build a bigger one.
Greg