Thursday, May 6, 2010

Tesla Coils

After playing with Rob's Tesla coil at Toorcamp, and catching some lightning off of it back at the lab with the Sword-of-Power and Daggar, I decided to build my own Tesla Coil.

Winding the secondary coil took most of the night, but Chicken was kind enough to let me use his coil winder:

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Eventually, I got it up and going:

TeslaCoil 01

To commemorate my success (and to help me remember how to put the thing together), I got a tesla coil wiring diagram tattoo on my left forearm.

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One night, Rob, Chicken and I all setup our coils. Bill Beaty brought a pony-keg of argon, and we had fun playing with fire and lightning.

Updated: I dug up the specs off the wiki:

--Parts list and specification--

Starting with Rob's BasicTeslaCoil as a default, I ran my own numbers.

Here are the parameters my (still in progress) basic coil. I crunched the numbers using Deep Fried Neon and Wolfram Alpha and TeslaMap.

15 kV Neon Sign Transformer (NST) from Berry Neon:
15000V * 0.06A = 900W supply

Ideal spark Length (inches):
Deep Fried Neon says L = 1.7 * sqrt(900) = 51"sparks.

Maximum cap size math:
60 Hz, 15000V, 60mA = 0.0106uF cap max.
Rob read somewhere that coilers multiply that times the golden ratio. 0.0106uF * 1.6180339887 = 0.01715uF

Actual cap size math:
8 x .15uF 2kV HV capacitors = 0.0187uF rated at 16kV

Secondary coil:
5" diameter acrylic, 20" coil, (4 to 1 ratio @ 5") 28 AWG wire (0.0126 bare, 0.0137 inches including insulation.)
Coil length is 20" using 1860ish feet of wire. And about 1424 turns. Inductance is 57 mH, capacitance is 8.5 pF.

Top load:
Teslamap says "Optimum Top Load Cap" = 17.09 pF
Toroid: 4" Ring Diameter & 16" Total Diameter = 17.4 pF
Sphere: 12" = 17 pF (I ended up going with a sphere)

Resonant Frequency:
130.9 kHz - Needed Primary Inductance 49.7 uH

Primary coil:

Should be 49.7 uH Based on 12 AWG : Primary Coil Wire Diameter: 0.0808 in Primary Coil Wire Spacing: 0.03 in Primary Coil Hole Diameter: 7 in Primary Coil Incline Angle: 90 deg

TeslaMap tells me I want 13 or 14 turns of this. 13 turns = 45 uH 14 turns = 51 uH

(For anyone interested in Tesla Coils, I highly recommend spending a whole bunch of time poking around with the DeepFriedNeon and TeslaMap calculators. Its taken me several weeks of saturating myself in the concepts before they're starting to make sense.)

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