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tesla sypathetic vibration

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teravolt

Sat Apr 29 2006, 03:55AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

In some cases when there is a high powerred tesla running and another secondary is set on the floor next to it, sparks will come off the sypathetic secondary that may only be grounded. Has anybody played around with this and tried resonating the sympathetic secondary to the active coil.

Shahn

Sat Apr 29 2006, 04:18AM

Registered Member #210 Joined: Sun Feb 19 2006, 08:25AM
Location:
Posts: 26

could be rather comlex!!!

Hazmatt_(The Underdog)

Sat Apr 29 2006, 07:35AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

I have footage of this but the charge cloud is rather weak. Just by having a similar coil in the field you can get some pretty good results. They do not need to be matched either. For example, my 2 nearly identical coils, one as the secondary in place with topload and the other sympathetic, would have 4" sparks from the sympathetic resonator even though its not at the optimal frequency. Now this is while I'm pumping ~700W.

I can also do it with the coil as a free terminal. I did this just for fun. I had the sympathetic secondary discharging to my toroid sitting on a stool, charging it. It was amusing, and had about a 3" charge cloud. It sparked from time to time. But like I say, I don't think I have any decent pictures because the camera was about 15' from the system.
I had to do it this way because of some EM problems, and even at that distance the autofocus went nuts once in a while.

Anyways, its really not that impressive. The 4 footers are more impressive.

What I could do though is maybe in the future make a small magnifier and see if there is anything to talk about. As is now, its really not that impressive.

Marko

Sat Apr 29 2006, 12:14PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Wee! My wireless power lives again!

As I could figure out, that's what Tesla messed with all the time.
I did some experiments, with small and medium SSTC's, and the smallest one seemed to work quite good (I had a resonator that I could tune closest to it's frequency than other coils).
I filmed it a while ago:

transmitting coil and resonator must be in exact tune.
My coil was small royer SSTC, operated at just about 10W at frequency about 1,5Mhz (I tried to get it as close as possible to resonator's frequency.
On the film you can see that I have a faraday cage close to the mini SSTC, and old TO3 heatsink hooked to it close to coil's topload.
It's not any kind of antenna/reflector as someone may think, but rather used to lower the resonant frequency to match resonator's frequency.

When resonator rings at the impedance of the coil it shows ot be infinite impedance towards earth and voltage on it can get very high, even higher than transmitter's voltage in very efficient systems (and we don't have such on this earth)

Current that flows to the resonator is determined by it's and coil's resonant frequency, and capacitance between toploads.

What is the capacitance between 2 ping-pong balls 1 meter away? Incredibly small, and so is the current, even at 1,5Mhz the coil was operated.

Multplied by the voltage on the resonator we get maximum power that can be transferred.

Voltage I got wasn't spectacular, probably just few kilovolts, and I relied more to the high operating frequency and tried to bring as more as possible current.

You can also see I supressed the breakout, as it is a big waste of power.

Still I managed to litght up a small 12V 1W bulb using stepdown winding together with neon (from old energy-saver bulb).

I also ran a 2W DC fan using fast diode from a TV tuner (that was hard to find) and a capacitor, so guessing I transferred about 2 watts at one meter this is 20% overall efficiency.

Considering also the low output voltage and enormous power waste of the transmitting coil (mosfets and secondary overheat in minutes, I even managed to melt the secondry in one long run!) this isn't that bad.

What is important for such power transfer in overall:

-Both coils must be resonant

-Both coils must have as big as possible toploads

-Both coils must run on highest possible frequency (note how it cancels one above)

-Transmitting coil must give highest possible voltage for power level (and lowest current, considering no-one will make an ideal tesla coil)

-The transmitting coil is the thing that is inefficient, not the transfer of itself.
Maximum power that can be continuously transferred is limited by the output voltage of transmiting coil, frequency and capacitance between toploads, but remaining power just remains inside transmitting coil's resonator, and considering it is 100% efficient we also get infinite output voltage and 100% efficient transfer no matter what is the input power.

You cannot compare capacitive coupling to things like radio, etc. because their efficiency dirrectly suffers from d^2 law, you can pick up diminutive part of it by antenna and even 100% efficient radio transmitter won't heelp its field not to spread out and go into space and be forever lost.

-Breakout should be suppresed if we want to keep our transmitter efficient.
Electric field is wanted, not sparks.

-I figured out, that grounding doesn't need to be that good as I firstly tought.
I tought that return-wire (capacitive coupling is another) must be of lowest possible resistance but I found that just closure of resonator base to metal bar under my table proven to be more than enough.

WHen you use resonator,, you will still be able to suck large amounts of power from it at distances far larger than ones where it stops sparkling.

You can also try winding few turns of thick wire around the resonator (tightly, for best possible coupling) and you can power bulbs, or rectify it an dpower various kinds of electronics, motors, etc...

(Firkragg found an interesting topic and has already written too much

)

teravolt

Sun Apr 30 2006, 04:19AM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

Thanks Firkragg and Hazmatt I have witnessed It to and it is interesting. This was tesla's goal to give people free power. If he only had semiconductors.

Avalanche

Sun Apr 30 2006, 12:19PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

Very interesting post there Firkragg.

I'm also experimenting with wireless power transmission, and it's interesting what you said about the transmitting coil should have a high voltage/low current, because I have had the best results with a very low coupling on the transmitter (flat primary spaced below the secondary). Winding the primary onto, or over the secondary coil simply induces large currents in the windings of the secondary - not what you want in a transmitter!

I will post my results in the projects section in the next few weeks. Basically the transmitter is a simple self-resonant SSTC, and the recievers are like an SSTC in reverse, with a bridge of ultrafast diodes on the *secondary* (careful!)

Marko

Sun Apr 30 2006, 01:41PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

All that seems nice but have you ever seen a resonator that will ring for next half an hour once excited? More than one second?
TC's are still inefficient stuff and they waste large amounts of power just to bring the voltage to some point.
Q drops with corona, (sparks, streamers if we let breakout) ohmic losses (ground resistance, wire high frequency), some dielectric losses, magnetic losses, etc.

So in reality you can't expect some miracles to happen, but you can always have fun

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