Kent Tinsley's Tesla Coil


The primary coil is made from 5/16" copper tubing with 18 turns currently tapped at turn 10. The secondary is made from 6" green PVC with approximately 995 turns of 22ga. magnet wire. It is space wound for the top two inches with 50lb. test monofilament fishing line. The secondary is capped on both ends with 1/4" plexilgass and a 1 1/2 X 3 inch piece of copper sheet inserted into the bottom of the coil so that it will plug into a mount on the primary coil.
The coil is an equadrive system with four rolled poly (Richard Quick/ TCBOR) capacitors. They are supposed to be .02mfd but I think that they only test to .017mfd. There are two caps in parallel on each end of the primary coil for a total primary capacitance of .017mfd.
The gap is two RQ/ TCBOR series gaps using 1 1/2 inch copper pipe with 7 electrodes at .028" gap. Instead of the fans blowing over the electrodes I cut out holes above each gap, sealed the ends with sheet mica and put two high volume fans drawing air through the gaps...vacuum gap. .336" total gap. I am using 1 1/4 inch heavy braided flat insulated copper tape/strap attached to the cast iron sewer pipe under the apartment for high frequency ground.
For NST protection there are two chokes on three inch ferrite cores, two sets of two parallel 50 watt resistors and a safety gap. There are no bypass caps. I also have two line pole type 10Kv lightning arrestors. I don't know whether they would actually do anything but they look cool. The toroid is four inch black flexible drain pipe 20 inches in diameter. The new untested toroid is eight inch aluminum drier duct 36" in diameter. With the old toroid and 12Kv .150ma of NST I was getting 47" multiple streamers. I am working on removing some shunts from a 12Kv .120ma unit to use with the other NST's (1-12/.060, 3-12/.030's). Inductances, K and Q factors etc. I have no idea. I believe that I figured all of that out in the beginning so that I could figure out capacitance and such but I don't remember and didn't make any notes. The newly inspired Terry Blake small asynchronous motor spark gap will go with the larger toroid and the rebuilt 12/......150ma? NST for the next round of testing and tuning.

I had actually quit coiling four years ago as my project got TOO BIG for my apartment. I thought that I would move and have a garage...I'm still in the same place. It's too cold to work on my truck and in my need to build something I started working on the coil again. I decided that my only neighbor is usually intoxicated so if the streamers go through the walls it's OK. I wanted to improve the gap and add some more power was where I left off. I didn't want to roll more poly and oil caps and thought that I would need to go to a potential transformer or a pole pig for more power.
I have found it really amazing that coiling is still evolving. People are using MOT's, MMC's, triggered spark gaps etc. This is all new stuff to me. I found your page using small sync. motors and your original idea of a lightweight rotor and multiple stationary electrodes. I had tried filing flats on a 1/2hp motor I bought and ruined the motor.
I used a scroll saw to cut the G10 for the rotor and a belt sander to finish shaping it. I haven't fired the gap yet. I am working on an unpotted 12/120 to add to the NST farm for 3200 watts. Feel free to post the pictures if you want. I attached a picture of my coil before I quit working on it. The insulators were free from the City Public Salvage.
I was so impressed with your rotary gaps that I made my own...maybe a bit over engineered. The stationary electrodes are carbide lathe bit inserts that I get from work. The rotary electrodes are 3/16 carbide cutter blanks that I use in die sinking. The rotor is heavy copper on both sides of G10 circuit board. The motor is a American Science and Surplus 22602 Shinano Tokki motor. I just wanted to thank you for providing the necessary information to build my gap and for the GREAT web site!

Kent Tinsley