I know I got it and I know it made it to the archives but did anyone
outside the mail server get this one?
Chip
---------- Forwarded message ----------
Date: Sun, 13 Apr 2008 17:15:44 -0700
From: DC Cox <resonance@xxxxxxxxxxxx>
Reply-To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
To: Tesla@xxxxxxxxxx
Subject: [TCML] Design for a classic mini-TC
I have completed a "classic style" design for a nice mini-coil. It is
portable, light-weight, uses only 3 Amps at 120 vac, and is ideal to
transport to schools, Boy-scout meetings, etc., for demonstrations.
It uses a 6500 VAC, 20 mA nst that has been modified (some shunts removed)
for operation at 50 mA intermittant duty. Also, uses 12 pcs of 0.22 1600
VDC MMCs in series (.0183 uF total), and a commercial high freq welder type
sparkgap (2 gaps) that is blower cooled (500 cfm). It can be constructed in
a small 13.5 x 9.5" wooden box, antique looking, and I used a 3/8 inch thick
granite tile (local flooring shop) cut to fit with 1/2 inch overlap all
around (again, for the antique look. Blower is fitted to one end with a
vent on one sidewall and exits out base vent for airflow.
I will be winding up a series of the secondary coils on my lathe. We are
using a fine 36 AWG wire with winding length of 8.75 inch x 2 inch OD on a
9 inch long vertical tube. The sec resonants at 512.4 kHz using a 2 1/2 inch
brass ball (McMaster-Carr or O.W. Langdergren). I could probably get a
discount on the 2 1/2 inch spheres if we all ordered them at the same time
in a bulk order. Spark output should be in the 5-6 inch range (may exceed
this performance). The complete design was done in JAVATC. Uses a 5.6 turn
primary of GTO silicone wire or it could be #6 AWG bare copper ground wire
slightly spaced. Coeff of coupling was set at 0.122 for good energy
transfer and performance.
If anyone is interested in purchasing some of these coils for their own
mini-coil, I will be running a group of them in May. I will furnish the
complete schematic with the coil. I also had to order the 75 pc minimum on
the caps, so I will have extra caps available. I can also furnish the high
freq welder spark gaps. You would mount them on some small insulators or
fabricate simple plastic stand-off insulators.
If there is enough interest I may offer a complete kit including coil,
sphere, spark gaps, caps, and even the xmfr. I get a price reduction on the
xmfrs as I order them in bulk for my large Van de Graaff generators. All
components new, not used.
If John Feau is still occassionally doing some toroid and sphere spinning,
perhaps he might be interested in doing a 2.5" copper sphere or perhaps a
small .75 x 2.5 inch toroid for these babies. The copper or brass look adds
to the antique look of the finished unit. I used some special antique sand
blasted copper laminate on the exterior of my boxes.
Please contact me off-list if you need the coil. I will also be selling the
completed coil with box, all parts installed, wired, and tested.
Dr. Resonance