Saturday, September 29, 2012

Miscellaneous oneTesla fluff

Several people on the internet are attempting to replicate my work, so I guess I should make a consolidated blog post about oneTesla...

Firstly, random construction tips:

  • Ground, ground, ground. It is absolutely essential that your secondary have a good ground; either a (good) mains ground, or a stake pounded several feet into the earth. Otherwise the driver (and other nearby electronics) will go berserk.
  • Don't plug the thing into a GFI outlet.
  • Don't get creative with the IGBT models; FGH60N60SMD's are currently $1.83 on Arrow, and are really the only transistors fast enough to comfortably drive a coil at 300KHz in musical duty.
  • Keep your resonant frequency between 200 and 350KHz. Too low, and the tank capacitor will overvolt. Too high, and the inverter will suffer from excessive switching losses. Of course, you could always go lower and use an external tank cap.
  • FOR THE LOVE OF TAYLOR SWIFT make sure the gate drive transformer is phased correctly; no amount of fuses will prevent your bridge from being destroyed if it shoots through with 50J in the bus capacitors.
  • Use a variac if you have one.
Secondly, interrupters: there's a couple of Kramnik's MIDI interrupter boards floating around. If you would like to beta test it, drop me a message privately (preferably on 4HV, the project thread is here) and we'll work something out. The board file for the interrupter is [here]; contact me for the polyphonic code since it isn't quite ready for public consumption yet.

Next, there's a semi-comprehensive troubleshooting guide [here]; please use it and give me feedback!

Finally, oneTesla is going commercial! Expect a Kickstarter and a full kit available in a couple months at the latest; the kit will have everything you need to construct the coil and polyphonic interrupter, and hopefully will be cheap and beginner friendly. Coiling will be brought to the masses! Be afraid...

I'll end with a photo, courtesy of Gao Guangyuan ("loneoceans"):

Serious business...also, GGY you're so good at taking coil photos!