Re: TCBOR TC Video Primer
>From rwall-at-ix-dot-netcom-dot-comWed Jun 5 22:37:11 1996
>Date: Wed, 5 Jun 1996 19:32:15 -0700
>From: Richard Wayne Wall <rwall-at-ix-dot-netcom-dot-com>
>Subject: TCBOR TC Video Primer
>This past Sunday night I fired my first Tesla Coil. The sparks were 18
>inches point to point. Pretty exciting for my first attempt.
>Secondary - 23 ga magnet wire wound on a 4 in dia PVC form x 26 in
>length. Sealed with four coats of polyurethane.
>Primary - 10 ga stranded Cu wire wound on a 6 in dia PVC x 17 turns.
>TX - 15 kV 30 mA Neon
>Gaps - 7 nonresistive spark plugs radially arranged around a 3 1/2 in
>PVC coupling. The coupling was drilled and tapped for the spark plugs
>which were wired serially. A muffin fan is mounted on one end of the
>coupling and blows across the gaps. The spark plugs are barely warm
>after several minutes of firing. Fouling has not occured. Has anyone
>else used this configuration before?
>Neon Protection - Two large split ferrite bead cylinders that snap
>around the HV leads. The inductance is 2-3 uH per bead. I placed a
>teflon sleeve over the lead and attach the ferrite bead around it.
>Multiple beads may be attached for higher inductance. They're rather
>inexpensive and rugged. I plan to measure pre and post ferrite bead
>kickback with a megaohm voltage divider and scope. I will post my
>findings. I also plan to add a protective spark gap and perhaps
>capacitors in the future.
>Caps - 3 x 40 kV Sprague doorknobs in parallel for 4.5 nF.
>Experimenting, I added another 1 nF glass oil filled cap in parallel.
>It heated fairly rapidly and blew up. Luckily no PCBs. A word of
>warning for those contemplating buying those caps with PCBs, caps will
>blow and the oil literaly explodes all over everything.
>Toroid - Four 3 in dia metal flu pipe elbows fitted in a circle and
>covered with aluminum tape. The outer diameter is 11 inches. There
>are eight straight sides on the outer circumference surface.
>Variac - Old 120 V 28 Amp "Variac".
>The secondary resonace is 402 kHz without the toroid and 381 kHz with
>the toroid. I did not have the material on hand to build a flat spiral
>primary, so I chose the helical primary. As I tuned it, I went all the
>way to the end of the seventeenth turn. I will need to add more turns
>for peak tuning. Also, I will build a flat spiral primary.
>I wish to publically thank TCBOR, and in particular Richard Hull, for
>their TC Video Primer. There is a wealth of information and technical
>know-how crammed into this excellent video. It is extremely accurate,
>informative and a real hands-on reference for any first time builder
>(or anytime builder).
Congratulations on your coil! Your spark length is not too shabby
for the size neon you are using, especially if you say you are not
yet finely dialled in. The real enjoyment of coiling starts now,
trying different system configurations in an attempt to squeeze the
maximum streamer length from your system. This can be a lot more
time consuming than the initial construction, but can provide
tremendous personal satisfaction as progress is made!
That spark plug multi-gap was clever, but I think you should
investigate a design that provides multiple large parallel flat surfaces
instead of the practically needle points you now have. The gap and
its quenching and curent carrying ability is one of the most
important functions of a coil system that cannot be overemphasized.
A less than optimum gap will cripple even the best otherwise
operating coil system in the world.
Welcome to the alternate lifestyle of living with a working Tesla
coil. Oh, yeah, if you've got a computer in the same room as you
fire in, unplug it! An RF line filter between the wall socket and
your neon is a really good idea. Grab one of those surplus units
salvaged from computer equipment made probably by Corcom, and connect
its ground to the same good ground (water pipe entry to the house,
etc.) that the bottom of your secondary
should be tied into, with heavy wire. For this power level #10 or
#12 AWG would be OK probably up to 20 feet.
Happy Coiling!, rwstephens