Wireless Power? (The work of Nikola Tesla)

[Desmond108]

Nikola Tesla's work has always fascinated me.

I've always heard stories and claims of Telsa's ability to be able to wirelessly power light blubs and I always found the idea intriguing. I've been doing some research on his experiments, or rather I've been trying.

I'm finding it pretty hard to find any concrete or reliable sources on what Tesla actually managed to accomplish. I read somewhere it involved large metal plates that generated an alternating magnetic field, which makes sense, but again, I've found nothing in depth.

Basically, I suppose what I'm asking is if anyone can point me towards some more in-depth or reliable sources that discuss Tesla's experiments, specifically things regarding wireless power?

It's just something that really interests me, any help would be appreciated :)

 

[phinds]

Can't help you with a source, but good luck with that. I find the guy interesting. Have read some about him and saw a good documentary on TV. Seems he was quite the genius and his wireless power distribution worked but was utterly useless for all practical purposes involving actual distribution of any significant amount of power over any significant distance. I believe I saw a calculation somewhere that showed that you could in fact have a nationwide power grid in the US using his technology if you were willing to permanently bankrupt the entire world for its construction and maintenance (AND you were willing to give up the staggering amounts of real estate it would have taken).

 

[MATLABdude]

If you haven't already seen it, there's a timeline (with references and links) over at the Wikipedia article on wireless power:
http://en.wikipedia.org/wiki/Wireless_power#Timeline_of_wireless_power

What would've been his magnum opus, the Wardenclyffe Tower (primarily intended for worldwide radio broadcasting, but also as a longer-distance electrical transmission demonstration) ran out of money before construction was completed:
http://en.wikipedia.org/wiki/Wardenclyffe_Tower

 

[0xDEADBEEF]

I think he basically used an alternating E-Field to power light bulbs. He stood on a stage inside a giant capacitor and was playing with fluorescent tubes. You basically just need a strong E-Field at some moderately high frequency to get the gas inside the tube into motion. A cheap way that produces very little light is just using the electrical field under transmission lines: http://pruned.blogspot.com/2008/02/fluorescent-field.html

I think he also did some near field magnetic transmission. And had some large ideas that never really got realized. See. MATLABdude's link.

 

[Meizirkki]

Sorry for necroposting, but I hope some of you will find this interesting.

I've replicated some experiments of Tesla. The wireless transmission is more like single wire transmission. The other end of the secondaries of the transmitter and receiver (tesla coils) have to be connected to each other with a wire or ground (earth) connection.

My miniature pancake coils have resonant frequency of about 9 MHz each. With this frequency, close range transmission via magnetic induction is possible. With longer distances, the frequency of transmission must be increased to pi/2 times the resonant frequency of individual coil. With my coils this is roughly 14MHz, but will vary depending on the ground connection. With this higher frequency, the distance between the two coils doesn't appear to have any effect on the transmission.

Tesla's method of wireless transmission is very different from the conventional radio to which it's most often compared to. In a conventional radio the energy is radiated everywhere with only small portion of it reaching the receivers. In Tesla's radio, the energy is conserved.

I've also been playing around with joule thief circuits, which have much in common with Tesla coils. A two watt joule thief made from scrap components can "wirelessly" illuminate any fluorescent lamp. I must say it is very rewarding to experiment with electric fields. Unlike magnetic fields, they seem to work over long distances. I'm already working on constructing another set of Tesla coils for further testing of wireless transmission.

 

[Alokin_Alset]

Hy Mezirkki.

My miniature pancake coils have resonant frequency of about 9 MHz each. With this frequency, close range transmission via magnetic induction is possible. With longer distances, the frequency of transmission must be increased to pi/2 times the resonant frequency of individual coil. With my coils this is roughly 14MHz, but will vary depending on the ground connection. With this higher frequency, the distance between the two coils doesn't appear to have any effect on the transmission.

¿ How did you get the resonance frequency? I could not find any formula for pancake coils, or bifilar pancake coils on the net & any physics book.

Why did you think that for higher frequencies the distance doesn't appear to be affected?

 

[Fischer777]

Tesla coils are another method Telsa used to transmit wireless energy, although, like the radio, they tend not to be very efficient. Nonetheless, they are simple to construct if you have the time and are willing to invest in them. If your interested, here's a website I've found to be very helpful if you want to undergo your own projects: http://deepfriedneon.com/tesla_frame0.html

 

[Meizirkki]

Hy Mezirkki.

¿ How did you get the resonance frequency? I could not find any formula for pancake coils, or bifilar pancake coils on the net & any physics book.

Why did you think that for higher frequencies the distance doesn't appear to be affected?

I didn't calculate the frequency. I winded two coils as identical as possible, except for the direction of winding, and measured the frequencies of standard induction and "Tesla transmission" with my schools equipment.

At the resonant frequency of individual coil I could induce electricity from one to another with distance of <2cm. The induction would fail whenever the coils were taken more than ~2cm away from each other.

When operated at the higher frequency I could leave transmitter into my room, and walk around the house holding the receiver, it's LED's shining brightly. I set up the coils for demonstration at my school's open house day and we also measure the efficiency of the transmission. 10 ohm resistor in series with the primary coil of the transmitter had a voltage drop of ~400mV and another 10 ohm resistor in series with the receiver's primary showed a voltage drop of ~380mW. This is 95% efficiency with a distance of about 6 meters. I expect it to be much closer to 100% with better coils and proper primary circuit.

In the above test, the transmitter was powered from a function generator and all voltages were RMS measure with an oscilloscope.

I'm planning to test my new coils at distances of over 100 kilometers, but it's going to take a while because building a powerful primary circuit for the transmitter is rather difficult :/

 

[Meizirkki]

Tesla coils are another method Telsa used to transmit wireless energy, although, like the radio, they tend not to be very efficient.

[citation needed] ?

Tesla coils is exactly the way to go for efficiency.

 

[jim hardy]

10 ohm resistor in series with the primary coil of the transmitter had a voltage drop of ~400mV and another 10 ohm resistor in series with the receiver's primary showed a voltage drop of ~380mW.

were both resistors in both circuits at times of both measurements?

and i assume you meant to type: 'primary showed a voltage drop of ~380 mV.' ?

 

[Fischer777]

I am curious about these pancake coils. Where can I get information regarding them (how they work and all that stuff)?

My miniature pancake coils have resonant frequency of about 9 MHz each. With this frequency, close range transmission via magnetic induction is possible. With longer distances, the frequency of transmission must be increased to pi/2 times the resonant frequency of individual coil. With my coils this is roughly 14MHz, but will vary depending on the ground connection. With this higher frequency, the distance between the two coils doesn't appear to have any effect on the transmission.

I am not sure I understand this. How can a resonant circuit operate outside it's resonance frequency?

When operated at the higher frequency I could leave transmitter into my room, and walk around the house holding the receiver, it's LED's shining brightly. I set up the coils for demonstration at my school's open house day and we also measure the efficiency of the transmission. 10 ohm resistor in series with the primary coil of the transmitter had a voltage drop of ~400mV and another 10 ohm resistor in series with the receiver's primary showed a voltage drop of ~380mW. This is 95% efficiency with a distance of about 6 meters. I expect it to be much closer to 100% with better coils and proper primary circuit.

How is the energy being transferred from the emitter to the receiver? Is it magnetically or electrically? Do the coils have to be aimed at each other for the transfer efficiency to peak?

Forgive me for asking what are probably really silly questions. I am a freshmen electrical engineering major with absolutely no formal training in electrodynamics whatsoever.

 

[Meizirkki]

were both resistors in both circuits at times of both measurements?

and i assume you meant to type: 'primary showed a voltage drop of ~380 mV.' ?

yes to both.

 

[Meizirkki]

I am curious about these pancake coils. Where can I get information regarding them (how they work and all that stuff)?

I am not sure I understand this. How can a resonant circuit operate outside it's resonance frequency?

There appears to be two resonant frequencies. The lower is for magnetic induction and the higher for electric field induction. Tesla stated that his wave travels pi/2*c (faster than light). The resonant frequency for Tesla transmission is also pi/2 times the frequency of magnetic induction.

How is the energy being transferred from the emitter to the receiver? Is it magnetically or electrically? Do the coils have to be aimed at each other for the transfer efficiency to peak?

According to Tesla himself, his radio was not magnetic and my experiments lead to the same conclusion. The transmission is achieved with the use of resonating electric fields. This way, the receiving coils acts like a capacitor in series with the capacitance of the transmitter. Or that's what I think. I've been trying to figure this out for many months now and of all the proposed explanations this makes the most sense. Coils do not need to be pointed at each other, the position of the coils does not affect the transmission.

And please don't apologize for asking those questions. It's so hard to find reliable information of the Tesla transmission that after reading some books and browsing through hundreds of shady websites I decided that the only way to understand it is to do it myself. I encourage you to do some experiments too. :)

 

[Fischer777]

Is a Tesla pancake coil essentially the same as a Tesla coil with the windings in a flat spiral instead of in a helix, i.e. there's a primary coil of a just a few turns of thicker wire, and a secondary that's several hundred to several thousand turns of small wire (with one end grounded and the other attached to a circular or toroidal capacitor)?

 

[Meizirkki]

Is a Tesla pancake coil essentially the same as a Tesla coil with the windings in a flat spiral instead of in a helix, i.e. there's a primary coil of a just a few turns of thicker wire, and a secondary that's several hundred to several thousand turns of small wire (with one end grounded and the other attached to a circular or toroidal capacitor)?

Yup.

EDIT: [According to Tesla's patents.]

 

[jim hardy]

so in your experiments are primary and secondary connected by this "ground" ?
If so, is it a wire between the coils or rods driven into Earth near each coil?

 

[Meizirkki]

so in your experiments are primary and secondary connected by this "ground" ?
If so, is it a wire between the coils or rods driven into Earth near each coil?

The primary and secondary coils are not connected to each other in either of my coils.

Did you mean to ask whether the secondaries of the pancake coils were connected? They are connected with a wire. Tesla himself used Earth in the place of this wire, but I haven't been able to test that myself since it would need a very good RF ground, and I don't have an Earth grounding of any kind. :/ Besides, using Earth ground would be rather difficult with coils this small. The pancakes are only about 15cm in diameter.

 

[sophiecentaur]

That danged Tesla rears his head again. I wonder what the FCC would have had to say about his experiments if he'd tried to carry them out today.

Amazing that all those high powered US tech. companies never took on board his 'fantastic' schemes. They certainly missed a trick there.

Reading what people have to say about our Nicola rather puts me in mind of the old Soviet history books that their Schools taught from. Read them and you'll learn that Soviets invented pretty well everything technological since the Revolution.

 

[jim hardy]

"""Did you mean to ask whether the secondaries of the pancake coils were connected? ""

yep, that was the question..errr, should have been the question..
just trying to get a handle on your setup.

Thanks !

 

[billbaty]

Most people think that Tesla was transmitting power through the air, probably because they see the towers he built, hear that he was transmitting power and associate his operation with modern-day radio transmitting towers.

What was actually happening is he was collecting electricity at the top of the tower and transmitting it into the ground. The ground was his wire. Look at his patent for the wireless transmission of power and the tower is labeled as a "generating" device.

Look up "Art Bell's Antenna" and he accidentally stumbled upon Tesla's electrical generating capabilities. I don't have all the stats before me but Art got a continuous 350 volts from a radio tower that was about 80 ft tall and had a loop of about 1/4 mile of #2 wire.

ll the best,

billbaty

 

[sophiecentaur]

Where did the energy, reputedly, come from?

 

[Meizirkki]

It has been rumored, but afaik not verified, that Tesla collected energy from naturally occurring electric fields. Wilhelm Reich was also known to "accumulate" electric fields in his accumulators (though he always called it something cool like "force of life and sexuality").

What we do know about Tesla coils is that in a well designed coil the oscillating field becomes very large and dies off rather slow. The Q factor is incredibly high, especially when operated at the "capacitive resonance" frequency, far higher than the usual resonant frequency. At this high frequency, the electricity no longer moves along the wire but along the capacitance between each turn of the coil. There is practically no current in an ideal Tesla coil secondary, which means there are no resistive losses and no magnetic-related losses whatsoever.

In his patents, Tesla is boasting how the upper terminal of his coil can reach "many hundreds of thousands of horsepower". This is not a lie for the coil maintains it's oscillation and even with a relatively small input power, the oscillating field can reach tremendous power over time. Tesla surely didn't have a continuous input power of many hundreds of thousands of horsepower. There is much confusion about this perceived "excess energy", but I hope the above has it in a nutshell.

But if Tesla indeed managed to collect large amounts of electrical energy somehow I'm all into replicating such work. I didn't look up the Art Bell's antenna yet, but it sounds reasonable. We are surrounded by many naturally occurring and man-made fields. Art Bell's antenna could be receiving anything from Earth's ELF signals to AM radio of >250KHz.

There's also this guy who designed and built a Tesla coil alike high Q AM antenna and tuned it to resonate at the frequency of certain radio broadcast. As expected, his antenna begun oscillating and up to 30 watts of power could be received from the distant radio station.

 

[sophiecentaur]

The above terminology is a bit far fetched. Power ( "Horsepower" ) is a transfer of energy and not 'stored energy'. It is true that a resonant circuit (or a standing wave) will store energy but this has nothing to do with power. It's all about having a fairly high Q circuit. But a good receiving antenna will couple well to free space so it will not have a high Q.

This stuff about 'collecting' energy from 'naturally occurring and man-made fields' violates thermodynamics and basic conservation principles that even Nicola cannot waffle his way around. I could suggest that he was probably well enough informed to be aware of this and that it's his disciples who have over egged his claims.

Many antennae have a larger effective cross section for intercepting a passing wave than their geometrical shape would suggest (a thing wire dipole, for instance) but the power has to come from somewhere and, once beyond the local field of influene, the energy flux over the sphere will not be affected. Where this "30 Watts" is supposed to have come from is anyone's guess. What was the original transmitter power and what was the separation?

Since Tesla died, technology has progressed an awful long way. People seem to be suggesting that his ideas were, somehow, so magical that they have never been understood by anyone since. This is despite GR, Quantum Physics, String Theory, even classical EM theory and the rest. There has, somehow, to be a subset of knowledge that Tesla had - some sort of magic- that has escaped all the brilliant minds that have existed since his time. Get real chaps. If they were real and worth money then we'd have them in our homes, transport systems and weaponry.

Instead, what have we got? Fizzy sparks for school kids.

 

[billbaty]

The energy is the Earth's magnet that has been concentrated. Electricity is concentrated magnetic flux. When you put a coil of wires in front of a magnet the flux is concentrated in the individual strands of wire. Tesla's tower, or Art Bell's, essentially concentrates the Earth's magnetic flux into a measurable amount of electricity when it is released or grounded, that is to say released to the ground.

We all have assumed that Benjamin Franklin flew a kite in a thunderstorm and got shocked. But what really happened is that he flew a kite in broad daylight using a copper wire for a string and when a certain altitude was reached and he touched the attached key, he ground out the concentrated magnetic flux and shocked himself.

billbaty

 

[sophiecentaur]

The energy is the Earth's magnet that has been concentrated. Electricity is concentrated magnetic flux. When you put a coil of wires in front of a magnet the flux is concentrated in the individual strands of wire. Tesla's tower, or Art Bell's, essentially concentrates the Earth's magnetic flux into a measurable amount of electricity when it is released or grounded, that is to say released to the ground.

We all have assumed that Benjamin Franklin flew a kite in a thunderstorm and got shocked. But what really happened is that he flew a kite in broad daylight using a copper wire for a string and when a certain altitude was reached and he touched the attached key, he ground out the concentrated magnetic flux and shocked himself.

billbaty

"Electricity is concentrated magnetic flux" is it? "Electricity" is, in fact, a non-specific term (in Science) which is used as a general description 'to do with' Electromagnetism and the study of it. There is Electric Field, Electric Potential and many well defined quantities - but not 'Electricity'. If you want to 'get energy' from something then you have to put energy in or there needs to be a change of some sort. This is basic stuff that has proved itself to be reliable and consistent enough to 'put a man on the Moon' and 'give us the Internet'. The standard theory could be said to have pretty much justified itself in most practical applications. If you want to propose a better theory then you had better start on a massive body of work and not just give assurances about things that happened in the dim past.
It's interesting that you quote Benjamin Franklin and not an experimenter of more recent times. Were you there to see "what really happened" and could you quote some figures to indicate just how much energy is available in this way? If it really were as you say it is, why don't we all have towers over all our houses to supply our energy needs? It's so wasteful to be burning all that gas and oil when towers could do the job. Set up a company and see if it makes you any money - based on results.

Actually, what you are proposing is outside the terms of Physics Forums in that it does not involve any peer- reviewed ideas.

 

[Meizirkki]

This stuff about 'collecting' energy from 'naturally occurring and man-made fields' violates thermodynamics and basic conservation principles that even Nicola cannot waffle his way around. I could suggest that he was probably well enough informed to be aware of this and that it's his disciples who have over egged his claims.

Why and how exactly does anything I suggested violate the laws of thermodynamics and basic conservation principles? My point was that whatever these "collectors" may be, they don't create energy but receive it from an existing source. And there are lots of sources around us.

Many antennae have a larger effective cross section for intercepting a passing wave than their geometrical shape would suggest (a thing wire dipole, for instance) but the power has to come from somewhere and, once beyond the local field of influene, the energy flux over the sphere will not be affected. Where this "30 Watts" is supposed to have come from is anyone's guess. What was the original transmitter power and what was the separation?

Here's the article. Just like a receiving Tesla coil, the antenna becomes a capacitor in series with the capacitance of the transmitter.
EDIT: He also used the regenerative circuit to increase the effective area of the antenna, sorry I didn't remember that one.
EDIT2: Nevermind, the regenerative circuit was only used in first of his tests, not the 30W one you were interested in.

Since Tesla died, technology has progressed an awful long way. People seem to be suggesting that his ideas were, somehow, so magical that they have never been understood by anyone since. This is despite GR, Quantum Physics, String Theory, even classical EM theory and the rest. There has, somehow, to be a subset of knowledge that Tesla had - some sort of magic- that has escaped all the brilliant minds that have existed since his time. Get real chaps. If they were real and worth money then we'd have them in our homes, transport systems and weaponry.

Instead, what have we got? Fizzy sparks for school kids.

I don't want to upset you, but I think Nikola Tesla is the only man to ever use the planet Earth's features as crucial parts of his circuits for wireless energy transmission. That is where everyone else have gone wrong. Tesla's wireless transmission system is very real and there's no magic: just think of the Earth and the atmosphere as capacitors and it will make sense. The energy is not radiated, it is conserved.

Peace.

 

[sophiecentaur]

Your posts and the link you have exhibit the same glaring flaw. That is there are no quoted figures and no serious experimental details.
All Science and Engineering involves details and numbers. That's why it tends to work when done 'properly'.
The fact is that there is no EVIDENCE to support this nonsense.
You either have to believe that there were successful results from the original work and they have been deliberately suppressed (conspiracy) or that no Scientist has had sufficient ability to take it to a successful commercial conclusion (cockup).
Else you could just admit to yourself that it's all moonshine.

That link is no more than a rather garbled version of a straightforward EM textbook. But with one thing missing - solid theory.

 

[Meizirkki]

I've provided details of my last experiment and given a reasonable explanation of how the transmission works, which obeys all laws of the prevalent physics. And once again I'm told that the tesla transmission is nonsense.

You have all the right to not believe what you haven't seen with you own eyes, but please keep it to yourself. It isn't very good science to come over and tell an experimenter he's wrong just because what he does isn't in the book.

And by the way, please don't take the link against me here. Whatever the author has written is his opinion, not mine. I agree with the idea of a resonant receiver becoming part of the transmitter circuit, but I don't have enough knownledge to comment on anything else he might have said.

 

[jim hardy]

i repeat, at first glance resonance looks a lot like energy creation but in reality it's energy storage.

Q being ratio of energy stored to energy dissipated per cycle,

a substantial amount of energy is expected in a high Q system that's gently excited at its resonsnt frequency.
But the energy came from the excitation source , in tiny little bits one cycle at a time..
That's why soldiers marching across a bridge break step.

If you ever lived with a Piano, you've heard individual strings come and go in sympathetic vibration with sounds in the room. Room sounds are the excitation source and each individual string is a high Q resonator.

I'm still waiting for a "Free Energy" experimenter to identify the source of excitation more specifically than "Earth's magnetic field" .. and not holding my breath on that one.

But i find your 14mhz transmission experiment producing 380 mv across ten ohms interesting.
That sure is one heck of a directional antenna pair!


old jim

 

[sophiecentaur]

I've provided details of my last experiment and given a reasonable explanation of how the transmission works, which obeys all laws of the prevalent physics. And once again I'm told that the tesla transmission is nonsense.

You have all the right to not believe what you haven't seen with you own eyes, but please keep it to yourself. It isn't very good science to come over and tell an experimenter he's wrong just because what he does isn't in the book.

And by the way, please don't take the link against me here. Whatever the author has written is his opinion, not mine. I agree with the idea of a resonant receiver becoming part of the transmitter circuit, but I don't have enough knownledge to comment on anything else he might have said.

I am "taking the link against" you because you brought it into the argument. You have used it as evidence and I am debunking that particular piece of evidence.

Your experimental results show that it is possible to get coupling between two circuits (a pretty common thing). In fact you have not given a 'reasonable explanation' for the results because they need to be analysed properly. And the results, in fact, tell you very little.

I question that your claim of 95% efficiency. To prove that, you need to be looking at Power and not just a voltage across a resistor. You can only use Current or Volts as a measure of efficiency if the impedances are the same. (A transformer can appear to be a fantastic amplifier if you don't obey the rules). Are you aware of what Jim is telling you about resonance?
What is the output power of your signal generator and the actual power delivered to your LEDs? It may be quite hard to determine this, actually.

You mention a School. I sincerely hope you are giving any students a balanced view of their Science and not taking them down strange, alternative paths. Young people are easily lead and the Tesla legend could be dangerously attractive.

 

[Meizirkki]

jim, in one of my posts I explained why Tesla coils have such high Q and that it's exactly what "excess energy" seeking people get so exited about. I hope it didn't give you the wrong impression that I would think there is excess energy. I see what you say and I completely agree. Also, thanks for the compliment :) but I must note that Tesla coils are not directional antennas in the traditional sense. They are more like plates of a capacitor, the entire space between them being the dielectric. A properly operated Tesla coil doesn't create large magnetic fields.

and sophiecentaur, sorry for not being clear enough in my previous posts. The resistor were of same type, 10 ohm (very close, measured with a multimeter) and the coils as identical as possible. The impedances were same and that's why I didn't bother mentioning current or power. Voltages are true RMS measured with an oscilloscope.

I don't think I'm leading any of my fellow students down a wrong path.. I'm an experimenter, not a theorist. I'm not one to tell people how things are, instead I show off Even our teacher was surprised when we lit up fluorescent lamps by holding them in our hands ;) (a joule thief buzzing in the background.)

 

[jim hardy]

"They are more like plates of a capacitor, the entire space between them being the dielectric. "

I did not do well in fields or vector calculus courses so can't offer any worthy commentary.
"... A properly operated Tesla coil doesn't create large magnetic fields.""
Yet i have read that E and B fields are inseparable..
So i just make mental note of experiments like yours , and if Fate ever wants me to understand fields better one of them will be an epiphany.
"When the student is ready a teacher will appear".
Meantime i just watch while folks like Sophie and Yungman and Bassalisk et al enjoy the advanced math.


Maybe we'll get back to an Aether and maybe it'll be anisotropic... some of my friends over at Neutron Repulsion toss about such ideas. I feel like Charley working in that bakery...(Flowers for Algernon)
Thanks for the clarification and thanks to all for letting me share your playground..

 

[sophiecentaur]

jim, in one of my posts I explained why Tesla coils have such high Q and that it's exactly what "excess energy" seeking people get so exited about. I hope it didn't give you the wrong impression that I would think there is excess energy. I see what you say and I completely agree. Also, thanks for the compliment :) but I must note that Tesla coils are not directional antennas in the traditional sense. They are more like plates of a capacitor, the entire space between them being the dielectric. A properly operated Tesla coil doesn't create large magnetic fields.

and sophiecentaur, sorry for not being clear enough in my previous posts. The resistor were of same type, 10 ohm (very close, measured with a multimeter) and the coils as identical as possible. The impedances were same and that's why I didn't bother mentioning current or power. Voltages are true RMS measured with an oscilloscope.

I don't think I'm leading any of my fellow students down a wrong path.. I'm an experimenter, not a theorist. I'm not one to tell people how things are, instead I show off Even our teacher was surprised when we lit up fluorescent lamps by holding them in our hands ;) (a joule thief buzzing in the background.)

But the 10Ω is not the Load, is it? It is surely just a current sensing resistor, not a power meter. Certainly you wouldn't light LEDs with 400mV. So how did you actually measure the POWER transfer involved? What was your load impedance and what was your source impedance, for a start?
I get the impression that your attitude to this business is tailor made for the Tesla religion. Just approximate enough to feel you understand the arm waving but not rigorous enough to use the Equations to tell you what exactly is going on and to keep you on the rails.

You are a student, I realize. It is great that you have enthusiasm. If you really want to follow this fondness for Science to take you into a career, you will need to go through the pain of formal treatment of all these things. You will then be able to see what you have read in its context. Take it from me, conventional EM is NOT WRONG. The terms you are bandying about have much more exact meanings than you seem to realize. When you have got some substantial knowledge of the topic then you can usefully take the subject into 'paid employment'.

If you want to beat 'em then you will have to join 'em first - like all the successful and celebrated workers have done. You seem to have a good, healthy disregard for 'excess energy', in principle - and that reassures me.But I think you need to see the overall picture and that a lot of what you are describing is, in fact, just that. These Energy Sources are not actually Sources - they are just (Low-grade) Energy Levels. There is loads of thermal energy in the Arctic Ocean - it's just not a lot of use because the temperature is so low. Likewise with your 'unspecified' energies that exist in the World. The Energy sources you hint at don't actually represent energy that can be utilised. Like I said, the Conservation Laws and thermodynamics can't be ignored. The Numbers count: use 'em.

 

[Meizirkki]

Okay, now I see that I wasn't clear enough. Sorry.

The LED test and the efficiency test were two separate tests. In the efficiency test, the 10 ohm resistor was the load impedance. The only component connected across the terminals of the primary coil, which means all the current in the primary goes though it. At the transmitter end, a 10 ohm resistor was connected in series with the primary and function generator, again all the current from the function generator goes though the 10 ohm resistor. My teacher was following the experiment and I can assure you I did everything with great care.

I hope I didn't upset you. I don't have a fraction of the knowledge and experience you have. I'll take your advice and learn more :)

I hope to take pictures and more accurate measurements of my new setup when it's finished.

 

[sophiecentaur]

Never upset - don't worry.
My point is that your 10Ohm resistor measurement will not tell you the power unless you know source and load impedances. If you have resonant systems it is even less easy. So, apart from the fact that you lit your diodes, you cannot know the efficiency.

But there are two entirely separate issues here. You have shown that it is possible to get good coupling between a source and load, using a transformer but that has nothing to do with the notion of getting energy from other, unspecified, sources of RF energy. You did not take my point about Conservation Laws, but they apply here the same as anywhere else and they are the basic objection to 'excess energy' and also to this. Going back a bit, you are actually suggesting the equivalent to a 'Maxwell Demon', which has been put to bed long ago.

 

[Meizirkki]

Never upset - don't worry.
My point is that your 10Ohm resistor measurement will not tell you the power unless you know source and load impedances. If you have resonant systems it is even less easy. So, apart from the fact that you lit your diodes, you cannot know the efficiency.

But there are two entirely separate issues here. You have shown that it is possible to get good coupling between a source and load, using a transformer but that has nothing to do with the notion of getting energy from other, unspecified, sources of RF energy. You did not take my point about Conservation Laws, but they apply here the same as anywhere else and they are the basic objection to 'excess energy' and also to this. Going back a bit, you are actually suggesting the equivalent to a 'Maxwell Demon', which has been put to bed long ago.

In my last two posts I have apologized for causing all these misunderstadings by not making my posts clear enough. No, it's not that. I read several previous posts of mine and I don't understand which part of them makes you think that:

- I am not familiar with the laws of thermodynamics and the conservation of energy.
- I have claimed that my coils would "collect energy"

I never claimed that Tesla coils had something to do with "collecting energy" nor did I make the slightest implication that my coils were in any way associated with the whole subject.

I didn't comment on your point about energy conservation laws and thermodynamics because I wasn't ignorant to them in the first place. You say that I was "suggesting the equivalent to a 'Maxwell Demon'".. I do not recall making such a suggestion.

Also, I must say I am slightly offended by your refusal to believe that I and the teachers of my school know how to measure efficiency.

 

[sophiecentaur]

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]

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/1QirnU-yX7XPJY_1MaW0UqU-egkO3-6WoxhcDQ3yiOyE/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]

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]

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.

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.

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.

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]

uhh I meant to say inductance, not impedance. (can't I edit my posts?)

 

[HallsofIvy]

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 referred 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]

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 referred 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]

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]

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]

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]

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]

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]

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]

Please do...I'm sure your input would be welcomed

The blog

[crackpot link deleted]