Driverless SSTC

[bismallah]

I tried following the circuit from Labcoatz for a driverless SSTC but couldn't limit the current properly. I tried using a 375W ballast which I measured to be 4.4H across the primary, and nothing happened which I think is due to the high reactance? The ballast itself is shown below and in order to properly use it should I short the secondary (I saw some do this with microwave transformers)? I also tried using two 40W lightbulbs in parallel in place of a ballast, and the secondary coil produced a measly 120V (should I try a higher wattage setup?).
Anyway, I tried the circuit without a ballast and it worked for a bit before abruptly dying. The tesla coil build and schematics are shown below, can someone please help?

[davekni]

Slayer oscillators like this are simple, but also finicky.

As with most electronic circuits, wire length causes problems.  Wires have inductance.  Tight layout and construction is required.  Especially the 1.5ke12 diode needs to be soldered directly to the FET.  1.5ke400 should also be fairly close.

There are plenty of counterfeit IRFP460 parts available.  I have no experience with "Bojack".  Their FETs may or may not have the robustness of normal industry vendors such as Vishay/Siliconix.

If you have access to a variac or other way to reduce voltage, I'd start below 120V.

[Andrew321]

I had some success with this circuit a while back. I wasn't able to get it to work at rectified mains because I couldn't seem to find a big enough inductor in my garage. I have a variac though and just started it at 12VDC and took it up to max current input. I think it was around 45VAC input for my setup. Still got some big parks off it, maybe 4 to 6"! Then I tried to audio modulate it with a 555 timer and ALMOST got it to work. but all my mosfets hated it and were killed

I could be misremembering, but make sure you have your coil directions correct. If noting is happening, try flipping your primary connections around. Also, as Dave mentioned, shorten long leads. I've had stuff not work for the life of me until I put the alligator clips away and soldered everything tight. Then it works like a charm!

Good luck!