Wireless Power? (The work of Nikola Tesla)


by Desmond108
Tags: nikola, power, tesla, wireless, work
sophiecentaur
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#37
Feb20-12, 01:57 PM
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Rather than saying the coils 'collect energy' it would be more appropriate to say that the 'couple energy' from one to another. That is a mutual effect involving 'near fields' and your receiving coil is getting its energy from a relatively high power source nearby. This is nothing to do with Mr Tesla but is good fun and a worthwhile experiment / demo.
Any structure will receive RF energy and radiate it in the same way that it will absorb and radiate thermal energy, in fact it's the same thing. The net gain or loss of energy will depend upon the total energy from all outside sources and the noise energy generated naturally within the structure due to the energy stored in it. It makes no difference whether you have a high Q or low Q, the totally energy available 'to use' from the receiving structure will just be equal to the flux of energy it can intercept. Any excess energy will be re-radiated. If you consider that the total amount of noise and interference energy (unless you happen to live just down the road from a powerful transmitter) passing through the area intercepted by a small antenna (or any structure) will be such that it will need amplification before it's easily detectable. Crystal sets are operating with relatively powerful signals and are the only 'passive' receivers you can make. These only make use of a mW or less of energy, from one or more powerful mf transmitters,not too distant. The net energy from all transmissions is of no use for powering any device but a sensitive earphone. No useful free energy. You would need to specify what other 'sources of energy' could provide any more than this. Magnetism is not a source of energy any more than the Earth's gravitational field is, on its own.

I question your measurement of efficiency because what you have described is not a valid way to find it.

Your contributions imply a connection between Tesla (you have championed his cause) and the results of your experiments. If there is no connection then perhaps a separate thread would have been better.

Your response to my objection involving Conservation Laws implies that you do not see the bigger picture and where they come into play.
Meizirkki
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#38
Feb24-12, 03:42 PM
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Hello again. I have a work trip to germany the next month, so I hurried to finish my new coils and take measurements before that.

Unfortunately for me, the efficiency was not at all what I expected. At first I couldn't believe my own calculations, since the results were so much better with the old coils. I checked photos of the earlier experiment and BUM. I found that in the earlier experiment, I had accidentally connected the scope probe in a way that short circuited the resistor I was measuring voltage from. The fact that both funtion generator output and scope probe are connected via PE ground had apparently crossed my mind. Thanks to the PE ground being such poor conductor for HF signal I still got results and considered the experiment a huge success.

https://docs.google.com/document/d/1...OyE/edit?pli=1

Thinking about it now, I find my own claim of 95% efficiency absurd. More than 5% is certainly lost already in the induction between the primary and the secondary. bah. I feel so stupid for not seeing that myself. Sorry.

My new coils aren't a complete failure though. Even with notable inconsistencies in the coils and sinewave input, the transmission did work. The efficiency, while being only a fraction of my previous claim, could never be achieved with magnetic induction at that distance (I tried that too), and with major improvements to design will definitely challenge radio transmission esp. at longer ranges. (correct me if I'm wrong)

At the very last, I hope this experiment provides enough evidence to show Tesla's transmission system is not "all moonshine".

I'm looking forward to improving the coils and designing a solid state power supply for the transmitter. Apart from improving the efficiency, I'm going to test whether distance has any effect on the transmission. If I can find faraday cages I will place the coils in them just to show the transmission is not based on EM waves and all energy radiated is energy lost.

Peace.
sophiecentaur
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Feb24-12, 04:26 PM
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Quote Quote by Meizirkki View Post
At the very last, I hope this experiment provides enough evidence to show Tesla's transmission system is not "all moonshine".

I'm looking forward to improving the coils and designing a solid state power supply for the transmitter. Apart from improving the efficiency, I'm going to test whether distance has any effect on the transmission. If I can find faraday cages I will place the coils in them just to show the transmission is not based on EM waves and all energy radiated is energy lost.

Peace.
Why should the basic working of a transformer system be attributed to Tesla? You may as well attribute it to Faraday - the only difference is the Iron core and the frequency.

I don't see why you would need a Faraday cage if you're planning to achieve 90% efficiency. Why should you care where the odd 10% is going? If you put it in a metal box, they you have even less idea about how the coupling is achieved and it would barely qualify for the name 'wireless' - more like a waveguide.

If you are using the separation distances that are referred to in 'that paper', you will be in the near field, in any case, so it won't be the radiated power but the 'coupled' power. When you say that it's not based on em waves, I'm not sure what you can mean. Do you mean 'free waves'? Because, if the power is not transferred by electromagnetism then you would have to invent a new set of fields to account for it. Is that feasible?

I can see that you think I am being a 'wet blanket' concerning Mr Tesla but do you not consider the possibility that you are re-inventing a wheel that has been re-invented many times before (including Tesla). If you want to optimise performance then you really need to look into the matching problem and what is basically an Impedance Matrix involving the self and mutual impedances of the two structures. Do some reading round and, apart from the term 'wireless' that has been hijacked recently, this sort of thing has been looked at many times. The difference in the situation these days is mainly the availability of cheap and efficient amplification and rectification and low power requirements for modern electronic equipment - which is probably why it is taking off again.

BTW, my ageing rechargeable toothbrush uses Wireless Power - but, as it's at 50Hz and needs to be small, the distance involved is not great.
Meizirkki
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#40
Feb24-12, 05:35 PM
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Quote Quote by sophiecentaur View Post
Why should the basic working of a transformer system be attributed to Tesla? You may as well attribute it to Faraday - the only difference is the Iron core and the frequency.
I'm only talking about Tesla all the time because this thread is about him and it's his work I'm trying to replicate. It's not my purpose to praise Tesla.

Quote Quote by sophiecentaur View Post
I don't see why you would need a Faraday cage if you're planning to achieve 90% efficiency. Why should you care where the odd 10% is going? If you put it in a metal box, they you have even less idea about how the coupling is achieved and it would barely qualify for the name 'wireless' - more like a waveguide.
I would do that only to show the energy is not transferred via radio waves.

Quote Quote by sophiecentaur View Post
If you are using the separation distances that are referred to in 'that paper', you will be in the near field, in any case, so it won't be the radiated power but the 'coupled' power. When you say that it's not based on em waves, I'm not sure what you can mean. Do you mean 'free waves'? Because, if the power is not transferred by electromagnetism then you would have to invent a new set of fields to account for it. Is that feasible?
Sorry, I'm confusing terms again. By EM waves I meant radio waves. I'm curious to how large this near field is, and how far it could be "stretched" with higher voltages and Earth grounding. And I forgot to mention, but that paper was made by me.

Quote Quote by sophiecentaur View Post
I can see that you think I am being a 'wet blanket' concerning Mr Tesla but do you not consider the possibility that you are re-inventing a wheel that has been re-invented many times before (including Tesla). If you want to optimise performance then you really need to look into the matching problem and what is basically an Impedance Matrix involving the self and mutual impedances of the two structures. Do some reading round and, apart from the term 'wireless' that has been hijacked recently, this sort of thing has been looked at many times. The difference in the situation these days is mainly the availability of cheap and efficient amplification and rectification and low power requirements for modern electronic equipment - which is probably why it is taking off again.
I might be reinventing a wheel that has been reinvented many times but I don't mind it. Even though the near field coupling is widely known and used, I haven't found anyone trying to do the same over long distances with the help of Earth and atmosphere. The only way to find out whether "Tesla was right" is to try do it myself.

With this more specific testing I've come to notice the same thing you say, the impedance and top/self capacitances of the coils should be exactly the same to achieve the best performance, but it's rather hard to do. It was obvious to me that my coils were somewhat out of tune when the output power could be improved by bringing my hand near the transmitter. I was tempted to take results while holding my hand there but I couldn't see the reading of output voltage on the other side of the room
Meizirkki
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#41
Feb25-12, 06:44 AM
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uhh I meant to say inductance, not impedance. (can't I edit my posts?)
HallsofIvy
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Feb25-12, 07:06 AM
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The problem with wireless power transmission is that you lose an awful lot of power through leakage to the atmosphere. Tesla could transmit power from one end of a stage to the other but not much further. (That's why "electrical engineering" used to be refered to as "power engineering" and "electronic engineering" as "signal engineering".)

The problem of loss is less with microwaves but there are other problems (it is far more dangerous to stand in front of a microwave beam than in front of a radio beam).
billbaty
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Feb25-12, 11:45 AM
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Quote Quote by HallsofIvy View Post
The problem with wireless power transmission is that you lose an awful lot of power through leakage to the atmosphere. Tesla could transmit power from one end of a stage to the other but not much further. (That's why "electrical engineering" used to be refered to as "power engineering" and "electronic engineering" as "signal engineering".)

The problem of loss is less with microwaves but there are other problems (it is far more dangerous to stand in front of a microwave beam than in front of a radio beam).
That's just not true. Tesla transmitted power over a hundred and fifty mile radius. He invented fluorescent lighting tubes that he placed on farms and ranches so he could monitor the transmission. These tubes were placed as far as 150 miles away from his tower and were to be witnessed by the farmers and ranchers. Tesla was hoping that the power transmission would extend at least 100 miles but tubes 150 miles away lit up. I have not read where he ever commented on how far the power could reach.
sophiecentaur
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Feb25-12, 12:06 PM
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You would have to provide substantial evidence than that about your claim about Tesla's demonstration. It's such an outrageous claim that you would need a lot more than some lines from a book.
It just has to be nonsense or you'd have to reject everything from Maxwell onwards in order to believe it.
This is supposed to be a Scientific discussion with its feet firmly on the ground and not fantasy.
sophiecentaur
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Feb27-12, 06:15 AM
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Quote Quote by Meizirkki View Post
uhh I meant to say inductance, not impedance. (can't I edit my posts?)
Is there not an Edit button at the bottom of your posts? I can always find one on my latest posts. It's on the same line as the 'Quote' button.

Yep - this is an edit.
Meizirkki
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#46
Feb27-12, 08:45 AM
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I've seen the button. I guess it just disappears after a while since I can't edit any of my posts now.

EDIT: Except for this one I just made. ;)
ontour
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#47
Mar5-12, 05:43 PM
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An Australian inventor is claiming to have found the solution to Tesla's Underground Wireless Transmission and is looking for input from experienced people in this field.
They are encouraging Universities to get involved by building a cost effective apparatus to demonstrate "proof of principle"
There is a google blog link in the "Serious activities Begins" section on the home page

[crackpot link deleted]
sophiecentaur
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#48
Mar5-12, 05:47 PM
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When that "Australian Inventor" has some theory or results to publish then I'm sure PF will be all eyes and ears. Until that, it's still Science fiction (by definition) and is not a part of PF world.

btw, only one conductor is needed to carry a guided wave. I thought simply everyone had heard of a Goubeau Line. That link doesn't seem to have heard of it, yet they're pontificating about 'earth return'. Probably not a good source of serious info.
Meizirkki
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#49
Mar7-12, 02:24 PM
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Solution? Pff. Like there ever was a problem? :P

EDIT: How on Earth is this something "that no one has ever been able to do before?" You only need two coils ffs. Should I call universities to see my coils too?

EDIT2: And he claims "all energy is transmitted via ground"? Not true.. I should contact him.
ontour
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#50
Mar7-12, 02:48 PM
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Please do...I'm sure your input would be welcomed

The blog

[crackpot link deleted]
sophiecentaur
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Mar7-12, 03:32 PM
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I'm amazed about the claim of 90% efficient transfer of power from one coil to another. What if another coil were put nearby? Would that get 90% of the power too? 180% of the input power would appear. That would be amazing good value.
Meizirkki
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#52
Mar8-12, 04:21 AM
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No. The input power would be shared between the two receivers. Tesla coils are "transponders" rather than transmitters and receivers.
sophiecentaur
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Mar8-12, 05:18 AM
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Quote Quote by Meizirkki View Post
No. The input power would be shared between the two receivers. Tesla coils are "transponders" rather than transmitters and receivers.
It's a transformer, in fact. Where's the magic in that? Not all transformers are made of iron and handle mains electricity.
I wish someone could tell me what's supposed to be different about these things with the name 'Tesla' attached to them. Transformer windings are essentially magnetically coupled coils because it is a near field effect and the impedance is not the same as for free space.
This way of close-coupling small pieces of equipment to a power source could have useful applications (subject to the interference levels being controlled). A 'charging table' would be another step up from 'the dock'. Efficiency need not be high because low power is involved.

But there seems to be some confusion about the distance over which this type of coupling exists. It is only in operation within a wavelength or so from the primary / transmitter. Only a 'free wave' will propagate over longer distances and energy can only be 'directed' using a large aperture antenna. Furthermore, the mutual impedance between wide spaced transmit and receive array is low (a receive antenna can't "suck" energy from the source). You cannot avoid 'wasting' most of your power and it is a brave man who disputes Maxwell's Equations.

People go and spoil it all by extrapolating a near-field process to long distance high power transmission as if it's the same thing. Tesla had a number of totally off the wall patents which are fully available for development but have never been (they were duff); there is no implication that a patented idea will actually work. Likewise, there may well have been uninformed pen-pushers in the Pentagon (or whatever it was called at the time) who decided that one or two of his untested ideas were a potential threat. There was no need to justify these decisions on rigorous technical grounds. Once declared secret, they were hidden from normal scrutiny and are not available for a healthy scrutiny /de-bunking. They just sit there, proving to the gullible that they are suppressed by that great conspiratorial body they love to hate. Tesla must be chuckling in his grave.
gushovard100
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#54
Mar9-12, 01:42 AM
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Tesla coils joined in single base wire connection format connect by conduction. Tesla lodged his first patent application that said transmission and then set out another Patent with virtually the only difference being the word conduction. It appears that the engineers at the time didn't get the conduction thing. And he didnt mean by EM he meant by wire connection. A simple single wire system I have built demonstrates conduction through one wire not magnetic transfer of power since both coils are 180 degrees out of phase. If they were acting as a transformer or by electromagnetic connection they would need to be out of phase to transmit energy using magnetic energy. It uses voltage and Amperage to do the job. Sure, it puts out a little EM radiation but very limited and usesless in the process since it is out of phase.


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