Tesla Coil Build Thread

[Atomicrox]

Progress on my SSTC has been real slow. so far I've assembled the interrupter on a breadboard and tested it with a piezo speaker:

And wound the GDT:

And here's my bed with all the components waiting to be used:

To-do:
-Driver (already designed on Fritzing)
-Bridge
-Tin foil the toroid

 

[DashApple]

Progress on my SSTC has been real slow. so far I've assembled the interrupter on a breadboard and tested it with a piezo speaker:

And wound the GDT:

And here's my bed with all the components waiting to be used:

To-do:
-Driver (already designed on Fritzing)
-Bridge
-Tin foil the toroid

Very Nice , good luck with the build , soon to see arcs we hope .

This was my latest Coil

Triac Interrupted Mini VTTC 811a - YouTube

811a VTTC secondary 2" x 2.5" , output 8.5 - 9.5 inches , harder to kill than Fets xD

 

[Sigurthr]

Very nice progress guys!

Atomic: now comes the hardest part in my experience; taking a working design from breadboard to PCB and still have it work. (Don't run the driver hooked up to the resonator on the breadboard, breadboards are just huge capacitive arrays at RF).

Twirly/Ion 555: I've been following your updates on YT, excellent work! I REALLY want to make a VTTC but every time I check out approximate cost for just barebones parts the estimate number climbs close to $300, if not more. I mean hell, most power tubes are $50ea, with another $20 for the socket this side of the pond. Even the cheaper tube designs require a hefty (expensive) filament transformer capable of many amps and several doorknob caps (~$30ea). To add to it all I don't even have a suitable B+ supply other than a single MOT/MOC/MOD (which only suits an expensive tube) or an old 300Vac heathkit transformer (which isn't enough to suit "small" power tubes).

I'm in the process of making an open-loop unregulated 12-600V boost converter (already achieved stable 12 to 130V using a scrapbox inductor and no gate drive chip, tested on a 30kV thermionic valve diode, got 0.75mA plate current which isn't bad considering it is meant for >15kV) that I should be able to use for a B+ for some 6146A beam power tubes I have from an old Ham rig. I also have a suitable filament transformer for the 6146As. At best I could get about 60Watts per tube, which would make a nice small desktop VTTC. I just need to figure out how to put it all together (I know the rough scheme, but I don't know how to determine values for the grid leak system or filament RF bypass cap or anode to primary DC blocking cap, etc). Then it is just a matter of saving up for and sourcing all the caps, power resistors, and sockets.

By the way I recently spoke with Steve Connor (an expert in solid state TCs) and he suggests there may be RF getting back in to the small signal stages of my driver. Once I complete Po-210's driver I'm going to try a new method of RF shielding on it and put it to the test. The small form factor and RF immunity that allows may greatly improve performance.

 

[Polonium210]

Very nice progress guys!
now comes the hardest part in my experience; taking a working design from breadboard to PCB and still have it work. (Don't run the driver hooked up to the resonator on the breadboard, breadboards are just huge capacitive arrays at RF).

There's nothing wrong with a breadboard coil :wave:

 

[Sigurthr]

Some guys have all the luck! When I tried it I blew the fets gates as RF got in to the GDT secondaries.

 

[Atomicrox]

Very Nice , good luck with the build , soon to see arcs we hope .

This was my latest Coil

Triac Interrupted Mini VTTC 811a - YouTube

811a VTTC secondary 2" x 2.5" , output 8.5 - 9.5 inches , harder to kill than Fets xD

Thanks! I'll do my best to get first light this weekend

That's a great VTTC, I love when small coils make a lot of sparks! Even more if they look swordish!

Very nice progress guys!

Atomic: now comes the hardest part in my experience; taking a working design from breadboard to PCB and still have it work. (Don't run the driver hooked up to the resonator on the breadboard, breadboards are just huge capacitive arrays at RF).

Some guys have all the luck! When I tried it I blew the fets gates as RF got in to the GDT secondaries.

Thanks! TBH I intend to test and optimize the coil with driver and interrupter on breadboard before moving to PCBs. I want to test many different designs before I commit to one
Hopefully it will work for m..

Did you hook the GDT secondaries to the breadboard? I intend to leave the GDT and everything "after it" soldered point to point.

 

[Sigurthr]

Okay news time! I finished Po210's driver boards and gave it a shot. I ran in to troubles with the interruptor receiver section of the main board and discovered design issues which I forwarded on to Po210. That being said the actual function of the driver seems to operate rather well. My only complaint is that it does not start oscillation as nicely as my own design, but this may not be an issue with Po210's board as I've had this problem once before when trying a PLL based board.

 

[Atomicrox]

Tried to get first light today... instead of sparks got a loud bang, a burnt up bridge and a black mark on my floor :/

Before it blew up the only output was lighting up a CFL some 40cm away.

 

[Sigurthr]

Tried to get first light today... instead of sparks got a loud bang, a burnt up bridge and a black mark on my floor :/

Before it blew up the only output was lighting up a CFL some 40cm away.

I'd say it is time for pictures!!! Sounds like you might have forgotten to reverse the phase of the lower fet's gate drive and drove both transistors into cross-conduction. Either that or some major layout/wiring errors. Pics and a schematic please!

Edit: on second thought you said it was transmitting some RF, which would not happen during full cross-conduction. So you may still have shoot through (partial cross-conduction).


I finished my 4046PLL driver, hooked it up, and tuned for exact resonance (quite a bear of a process using a micro 10k 270deg trim pot for phase adjustment!) on my main SSTC. Excellent results were obtained! Up to 15" streamers @ 130Vdc bus voltage, fets running cool at full power, and I can even audio modulate now. Self-start oscillation is working beautifully thanks to the VCO and it seems to be tracking streamer loading well. No more noise or momentary hiccups in the arc. Very happy.

When I get some time I'm going to use PO210's driver for my mini coil after I give it some more tweaking. Either that or make a smaller version of my standard driver and use that.

 

[Atomicrox]

Thanks for your help at 4HV! I can draw the schematics if you want but it's pretty much a mix of Po-210's driver with Steve Ward's interrupter and bridge.

I'm quite sure I got the phasing right. I did it according to oneTesla's manual.


Video of the audio modulated coil, please

 

[DashApple]

I'd say it is time for pictures!!! Sounds like you might have forgotten to reverse the phase of the lower fet's gate drive and drove both transistors into cross-conduction. Either that or some major layout/wiring errors. Pics and a schematic please!

Edit: on second thought you said it was transmitting some RF, which would not happen during full cross-conduction. So you may still have shoot through (partial cross-conduction).


I finished my 4046PLL driver, hooked it up, and tuned for exact resonance (quite a bear of a process using a micro 10k 270deg trim pot for phase adjustment!) on my main SSTC. Excellent results were obtained! Up to 15" streamers @ 130Vdc bus voltage, fets running cool at full power, and I can even audio modulate now. Self-start oscillation is working beautifully thanks to the VCO and it seems to be tracking streamer loading well. No more noise or momentary hiccups in the arc. Very happy.

When I get some time I'm going to use PO210's driver for my mini coil after I give it some more tweaking. Either that or make a smaller version of my standard driver and use that.

Nice Work , Do love the 4046 Ic's , i only managed 6 inch Arcs with mine though , Smoothed DC supply that is . plus a deformd secondary

 

[Sigurthr]

Here's the video:
Audio Modulated Phase-Locked-Loop SSTC - YouTube


The corona bush is about six inches tall with a couple of 8 inch spikes. If I drop the bus capacitance down to about 40uF (from the 1880uF shown in the video) I get 15" long spikes, but it is SUPER LOUD. I've got another 2200uF I need to add in at some point as well.

 

[Atomicrox]

Cool!

 

[Sigurthr]

Just a minor update as well;

I managed to work the gremlins out of my Po-210 driver (not his fault, we think my ICs are slightly different than his and incompatible with his board's topology) and got it running very well with my modifications. I'll be using it with my small secondary once the toroid and bridge heatsink come in the mail from EVR. Hope to make a very portable table top coil out of it.

4.3.13: Got bored and made this from old parts:
http://youtu.be/JmyGG4kV328

Yes that is a water bottle I cut holes in for 1/4-20 bolts to make a spark gap out of. Secondary is 7" of 30ga on a 3.25" coilform, raised up about 5" off the table on some pvc couplings. Primary is 5 turns of 10ga on a 4.5" coilform. MMC is 17.7nF, NST is a 7.5/30, coupling is modeled as 0.124K. 7" multiple streamers.

 

[Atomicrox]

Nice coil, Sig!

 

[Atomicrox]

Managed to get first light and about 5 runs of up to 30s before it blew up again:

This time I'm quite sure the high side gate resistor shorted to Vbus+ and the source pin of the MOSFET exploded (again). The rest of the bridge suffered minor damage and I think I'll be able to fix without rebuilding.