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Few hundred watts coil to coil wireless energy transfer

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LAN_403

Mates

Sun Sept 13 2009, 06:26PM

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

Hi guys,
This weekend we had telasthon in Czech Republic which will be introduced in details in a specialized thread...

One very interesting thing happened during this occasion which Iâ€™d like to show and discuss in this thread:

I plugged my single switch 2500W SSTC

in to the wall and to my big surprise a nearby (1,5m) standing VTTC coil of a friend of mine started to produce very nice streamers too, while my streamers were significantly smaller than usual. We all were pretty surprised by this phenomenon and we did a lot of experimenting with these two coils. We found out, that we can tune the receiver coil by changing the position of the contact on the primary which is a bit hard to understand for me...

We made some videos of these two coils which also show that by touching the streamers of the receiver coil we affected the streamers and also the sound on the transmitterâ€¦ Those two TCâ€™s were simply interconnected!

Has anyone seen something like that?

Iâ€™ll post the movies soonâ€¦

Notice the difference in the sparks shape between the transmitter and reciever coils.

This image shows the receiver VTTC when is plugged (turned on). Look at the shining tube - just to believe me! It also shows funny thing - the energy transfer works only one way.

EvilTesla-RG

Mon Sept 14 2009, 12:55AM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

Very Interesting!!

It doesn't actully surprise me, as Tesla's "Magnifing Transmitter" was just what we now call a Tesla Coil with and extra unattached coil.

I have only built two SGTC's, so my knowledge is limited.

But perhaps this isn't actully inductence apon the VTTC's secondary coil, perhaps it is coming through the ground? or the Primary?

I am wondering this becouse you said you can tune to your SSTC by adjusting the VTTC's primary. That the Energy Transfer is one way, and finaly that the sparks have a differnt shape and size than the SSTC (sugesting a differnt frequency).

Just theorizing

Steve Conner

Mon Sept 14 2009, 09:41AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

The two resonators are connected by capacitive coupling, and the VTTC primary is connected by inductive coupling, all into a single system with three resonant frequencies. Changing any component of the system affects all of the resonant frequencies, which is why adjusting the primary circuit of the VTTC had an effect.

I've run a PLL-driven twin DRSSTC like this, and by locking the PLL to the appropriate frequency, I could get streamers from the driven coil only, or the freestanding coil only, or both.

What I could not do was get the streamers from the two coils to connect, as they were 90 degrees out of phase due to the capacitive coupling.

Connecting the secondary bases together instead of grounding them fixes this by forcing the phase shift to 180', but it also means that you lose one of the three resonant frequencies, and always get streamers from both coils.

...

Mon Sept 14 2009, 05:55PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Looks a lot like the effect I observed,

Our resonators weren't anywhere in tune, so I only got streamers maybe 1/2" off the tertiary, but because of the reasonably high power of the driver (peaked about 500w) I was able to get some pretty juicy sparks out of it

Proud Mary

Mon Sept 14 2009, 08:00PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

I don't usually comment about Tesla business, being not much experimeneted in the business, but this seems to me a clear case of sympathetic oscillation.

teravolt

Tue Sept 15 2009, 01:57AM

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

I'm also thinking that the primary on the VTTC is a parallel tank circuit witch might help to trap some of the energy that is recieved by the secondary like a flyweal. If you had a current transformer you could verifie this.

Herr Zapp

Tue Sept 15 2009, 03:44AM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

Mates -

Did these two coils share any direct electrical interconnection (common RF ground, common AC line ground, etc)?
What were the resonant frequencies of the two systems?

At the 2001 NorCal Teslathon in San Francisco, a similar phenomonon was observed between two very large spark-gap coils. Greg Leyh and Kelek Stevenson had their coils set up within 30 feet of each other, and Kelek's UNPOWERED coil would generate 4-6' (that 4-6 FOOT) streamers when Greg was ramping up the input power to his coil. Kelek's unpowered coil would generate the greatest streamer length just before Greg's coil would start breaking out, and then as Greg's streamer length increased, Kekek's diminished. Still, 6' streamers out of an unpowered Tesla coil is pretty amazing (at least unpowered by it's own tank circuit).

After a fair amount of discussion, the consensus was that the largest contributor to coupling between the coils was electrostatic, but that electromagnetic coupling and some base drive from a common RF ground may have also played some role.

Greg posted some comments about this phenomonon on the Tesla Coil Mailing List on July 10, 2001 ("NorCal Teslathon -- Interesting Devices and Effects"). His post triggered multiple posts describing similar observations from other coilers on a whole range of secondary sizes and power levels.

Regards,
Herr Zapp

Mates

Tue Sept 15 2009, 06:09AM

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

Hi guys,

I was sure that once there are multiple coils on a small place there must be effects like this quite commonâ€¦

Based on your responses Iâ€™m still not completely sure which part of the receiving coil is the receiver. Is it the secondary? It is a bit strange than because the secondaries have obviously different resonant frequencies. My coil is oscilating at 340 KHz while the VTTC coil at 220 KHz. Does it mean that we saw only a trace of possible energy transfer and the efficiency would be much much higher in case the coils would resonate on the same frequencies? And my next question, how the 340KHz oscillations could have been turned into the 220Khz?

Herr Zapp wrote ...

Mates -

Did these two coils share any direct electrical interconnection (common RF ground, common AC line ground, etc)?
What were the resonant frequencies of the two systems?

With the ground it is a bit funny too. My coil was grounded to AC line ground while the VTTC used a metal plug buried in the garden.

BTW: A bit out of this topic, but I have also a question on the wireless projects sometime discussed on this forum, like the one Marco introduced recently

- are the two coils connected in the same way like we see here? I mean, does the presence of a receiver affect the properties of the transmitter (oscillation shift, changes in power consumption etc.)?

Cheers Mates

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