oneTesla

For those of you who have working oneTeslas, post a photo of your longest spark, and some measurements, here!
"Spark length" is defined as the total arc length (including curves) of the streamer - the coil is only 18" tall and can ground strike quite a bit further than that.
For starters, our longest streamer measured around 23"; frame from video attached. This was done with the release version of the interrupter firmware, no changes to the pulse widths.

Feel free to recompile the interrupter to run longer pulses, etc, but keep in mind the coil gets much less reliable if you push the pulse widths. If you're going for really long arcs, a grounded metal target on a pole helps direct the arc the direction you want it. We're not responsible for any exploding IGBT's during such shenanigans.
Have fun!

mine, about a inch...

Mine is perhaps 2 inches, but at half power. This is with a home-brew toroid, of the correct dimensions but not perfectly smooth (ribbed tubing covered with metal tape). I don't dare turn up the power beyond 1/2, because last time I did that I fried most of the high voltage semiconductors. I have a small supply of spares now, but they are cumbersome to replace. I suspect my primary and secondary are not in tune for some reason. I will measure the resonance frequencies tomorrow before I dare turn up the power setting.

EDIT: Measured the frequencies. My coil is rather badly out of tune. Primary 250 kHz, secondary 330 kHz. Strange. I have a top load of the correct size and shape. I will not crank up the power until this is solved.

15 inch ground strikes. But only around 200 watts.

http://www.youtube.com/watch?feature=pl ... O4VceLEwWw

Is this little device supposed to be able to dissipate more than 200 watts? I would expect the normal operating conditions to be well below the 10A fuse rating.

Watts = Amps x Volts
On the video it was drawing 1.4 amps
1.4A x 120V = 168 watts

I've had this coil pull 600 watts but only for a short time.

Well the hundreds of watts are going into the spark, not the driver - it isn't really being "dissipated".
For example, a 400W rated IGBT can switch a few thousand watts - the power rating means at most 400W can be lost in the transistor itself.

I'm sorry if I was unclear - English is not my native language, so my use of electrical engineering terms may be confused. By "dissipation" I meant the total power drawn from the AC mains. I would still consider the power that goes into the spark to be a part of what is "dissipated by the device", even though it's not being lost into the heat sink. What I meant to say is that I thought that the current drawn from AC mains would typically be well below the 10A fuse limit under normal working conditions.

I have no AC current meter at home, but I am seriously considering getting one. I would like to know whether my failures are due to the current being too high on an average, or if there are sudden bursts of high power due to glitches in the main circuit or in the interrupter.

Some numbers for a oneTesla coil that works correctly would be really useful for testing and debugging. A few videos on short test runs would also help a lot. It would be helpful to know things like how much power is typically pulled from AC mains under different power settings when playing a certain note, what the spark looks like under those conditions, and what the RF frequency of the bursts should be if the secondary is correctly in tune.

I've measured about 750W when pairs of high notes are playing at once; typical draw is about 3-400W during songs (real power as measured by a wattmeter).