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).