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Steve's Q.C.W coil design

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LAN_403

dex

Thu Mar 18 2010, 06:44PM

Registered Member #2566 Joined: Wed Dec 23 2009, 05:52PM
Location:
Posts: 147

Steve Ward wrote ...

The ability to generate a variety of shapes allows you to control the behavior of the spark. Slow ramping causes the spark to wander and curve, too fast causes the spark to split or sometimes become gnarly and kinked. You can change the ramp rate throughout the spark to give distinct features to it as it grows... the spark channel is itself the breakout point for future growth.
If only i were a PHD in plasma physics, i could probably get published if i wrote something :P.

Well,you can measure secondary current waves and compare it with the spark effects observed.
That should provide some info in a start.

Mates

Thu Mar 18 2010, 06:56PM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

It might look like Dr. Spark spreaded misinformation (some might understand his posts in that way...). There are no tubes involved in this coil design. In case they are I eat my hat.

Cheers Mates

Arcstarter

Fri Mar 19 2010, 02:26AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Mates wrote ...

It might look like Dr. Spark spreaded misinformation (some might understand his posts in that way...). There are no tubes involved in this coil design. In case they are I eat my hat.

Cheers Mates

I will tear a laptop screen apart and eat the plastic film inside!

Steve, we do not need you, we have put this among ourselves to figure it out!

TeslaCoilBuilder

Fri Mar 19 2010, 12:14PM

Registered Member #138 Joined: Sat Feb 11 2006, 10:23AM
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Posts: 9

Only 12 inch long, but I run it without modulated bus voltage and only 130Vdc on the bridge fres is also a bit lower (~325kHz)

Mates

Fri Mar 19 2010, 08:56PM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

I have a provocative question for Steve...
Is it the fact you have some commercial or letâ€™s â€œpublicationâ€ plans with the new coil setup, that you donâ€™t want to reveal any details (thatâ€™s of course fully understandable) or is it because you actually donâ€™t know what you are exactly doing that the streamers are so cool and â€œdoing what you want" and you just empirically run into this phenomenon?

Mates

Btw: My guess about this setup is quite simple â€“ valve (like a big IGBT or SRC) is in series with the bus and is driven by some kind of PW generator like tl494.

Steve Ward

Fri Mar 19 2010, 10:17PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

Is it the fact you have some commercial or letâ€™s â€œpublicationâ€ plans with the new coil setup, that you donâ€™t want to reveal any details (thatâ€™s of course fully understandable)

I might wish to write some paper for publication. But, im tired of people ripping off my stuff and putting very little effort into it themselves. Ive given away a fair amount of details and ideas, figure it out yourself if you think its easy.

or is it because you actually donâ€™t know what you are exactly doing that the streamers are so cool and â€œdoing what you want" and you just empirically run into this phenomenon?

The only part i dont fully understand is the physics of the plasma itself. Making the sparks straight was no accident, completely part of the design from the start, but it was based strongly on previous experience with quasi CW coils.

Btw: My guess about this setup is quite simple â€“ valve (like a big IGBT or SRC) is in series with the bus and is driven by some kind of PW generator like tl494.

Its not a bad guess, and the design doesnt have to be as complex as what im doing, its just a question of the performance you expect. I happen to be quite comfortable with embedded micro-controllers and classic control theory applied to power electronics, both things make this project more advanced than your typical DRSSTC. To educate everyone who wants one of these gizmos to the level of understanding of the technology that i have is just not something i want to do (go to school and get your own EE degree, you'll be better off!). And yes, i do enjoy that my work has performed so well, but no im not trying to rub it in anyones face. If you notice, i wasnt the one to bring up the subject of my work in the first place.

I think anyone who is capable of reproducing my results already knows enough to design it their own way anyway, so im gonna leave it at that for now. Perhaps all they needed to know is *that* it could work so well, and now its just a matter of implementation.

I will soon record some various measurements of this system under different sparking conditions as i believe this would stimulate some great discussion.

hvguy

Fri Mar 19 2010, 10:48PM

Registered Member #289 Joined: Mon Mar 06 2006, 10:45AM
Location: Conroe, TX
Posts: 154

I built a coil very similar to Steve's about a year ago. It was a 4KW, power factor corrected, modulated SSTC with a ~7KHz band width that was designed to explore high power audio modulation. The results where good, I could get a 24" full audio flame but the audio quality was not quit as good as I had hoped for and the project was exceedingly expensive. There is still so much research waiting to be done with very high power (+10KW) CW systems, but, honestly, this stuff is far beyond the average coiler in terms of both budget and ability. The time it would take to document everything, publish it, and answer the inevitable slew of questions is just too much for anyone with a life outside of the project. I understand and agree with Steve's approach to his, very cool, system and I do feel that anyone capable of building something similar will likely use the knowledge gained from his videos, pictures, and this thread to move forward with a design of their own. I say good on Steve for putting as much as he has out there...

cjk2

Fri Mar 19 2010, 10:50PM

Registered Member #51 Joined: Thu Feb 09 2006, 04:17AM
Location:
Posts: 263

I am quite interested in trying this with a buck converter as you used and a PLL based driver. Care to comment about the power requirements of this coil?

Steve Ward

Sat Mar 20 2010, 01:14AM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

The coil runs from 240V mains, Hankensteins amp meter said i was using about 15A typically. I havent done any serious power measurements for wall plug consumption other than that. I dont actually have power factor correction on this system since it was a prototype and i wasnt worried about getting the current draw way down. You can always operate it at like 1 pulse per second and just use a big filter cap bank and run it from a normal 120V 15A outlet. For my system the primary current is limited at 140A, this equates to about 100A peak from the synchronous buck converter, so keep the duty cycle low.

hvguy

Sat Mar 20 2010, 02:32AM

Registered Member #289 Joined: Mon Mar 06 2006, 10:45AM
Location: Conroe, TX
Posts: 154

I'm having site issues so the pictures associate with my post are no longer available as links, here they are for reference.

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