Talk:Wireless energy transfer

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Contents

[edit] Microwave section

Microwave transmission is seriously out of date. Kyoto university and other Japanese research institutions in cooperation with industry have performed lots of research ( http://www.kurasc.kyoto-u.ac.jp/jusps/ , thats just as of 2003, they are definitely further along by now ) and experiments, and they operate at relatively high efficiencies and power levels. Savuporo 12:05, 18 May 2007 (UTC)

[edit] Major Edit

Ok, I went through and did a major edit of this article. I tried to de-teslaize it but that needs more work and still needs citations. I also reorganized and included new sections for the various methods of wireless energy transfer as well as some minor reworking of the intro and description. I'm going to go link tracing later to fill in citations, but any help there is appreciated as I have never done this before. –AeoniosHaplo 09:42, 19 December 2006 (UTC)

Ok, little update. I still haven't gotten around to doing the citations, but the more I look at this the more I realize how broad an article this is, and the citations for it are going to be fairly nightmarish. After reading through the wikipedia editing guides, I've also decided to do a bit of a rewrite of the types section and add a comparison section additionally. The comparison section will also contain usages for each type, so the final usages section will get nixed in the process. I also plan on going through and enhancing this talk page so we have a bit better global organization for it. Right now the plans are kinda fuzzy and it's making prioritizing of work difficult. I hope to be able to dedicate a lot of time to this soon. AeoniosHaplo 10:38, 21 December 2006 (UTC)

Further update. I looked once more at the references section, and found a load of sources dated 1900-1920. The references section apparently needs to be de-teslaized too, and needs a serious cleaning in general. *Sigh*. I'll probably burn through that first as it's gonna have to be done in order to properly cite anything. AeoniosHaplo 10:59, 21 December 2006 (UTC)

[edit] Medical Implants

In response to a question from me, Geoffrey Wickham provided very helpful information on my personal page, which could maybe be incorporated here: http://en.wikipedia.org/wiki/User_talk:Cfrjlr#Reply_to_request_on_artificial_pacemaker_talk_page

—The preceding unsigned comment was added by Cfrjlr (talk • contribs) 15:28, 3 March 2007 (UTC).

[edit] Question to Wireless Energy Transfer Pros

1 - Is there technology currently available to provide wireless energy or means for wireless recharging? (I know of a company, SplashPower that provides wireless recharging of portable devices by placing the devices on a mat) I'm researching available technologies and products to develop next generation devices that can be powered wirelessly (phones, watches, laptops, mp3 players, keyboards, mice, etc.)

There are quite a few technologies that utilize wireless energy transfers. A very prominent example is RFID. The primary methods are electro-magnetic coupling (known informally as "backscattering") and inductive coupling. As well, you might also be interested in the Hall Effect devices. Current probes that clamp around a wire use it to determine the amount of current traveling through the wire by the induced magnetic field. FoxFord 21:27, 14 October 2006 (UTC)

The answer is yes - Inductive Power Transfer, or academically now referred to as Inductively Coupled Power Transfer, as Wampfler of Germany now holds IPT as a trademark. Unlike all these wussy consumer chargers Wampler and Vahle transfer significant power (1-100kW range) in industrial applications. Daifuku and Shinko(sp?) make similar products for ultra clean room automation. All companies deliver efficiencies of 80% or better over gaps of 10mm on guided tracks. Electric Bus charging stations are made that transfer over 4-5 times as much a gap.

2 - I've done a little bit of research on Tesla's findings on wireless energy transfer(WET) and am intrigued to explore new possibilities of WET. For example, would it be possible to develop a device that plugs into an outlet to transmit energy to all electronic (energy dependent) devices in that room (or within a certain distance)? From my findings, it seems that each dependent device would need a special energy receiving chip to be compatible with the transmitter. (There is currently a company that offers "wireless extension cords" which transmit energy via micro waves) but has many limitations and potential side effects due to the nature of the energy.

I think what you're referring to as "wireless extension cords" is a thinkgeek joke seen here: http://www.thinkgeek.com/stuff/41/wec.shtml . To my knowledge, no one has produced such a device. There are many limitations that would limit the application of it. Power dissipation would occur very rapidly, and the ability to convert from a very high frequency signal to a 60Hz 120VAC signal with the proper current delivered would be incredibly difficult. As well, the practical limitations of diodes to create a full wave rectified signal would also come into effect. FoxFord 21:27, 14 October 2006 (UTC)

Your comments are appreciated.

  • Lol. In reality that would work as advertised. However, it would indeed fry anything in the line of sight of the sending beam, including (permanently) computer equipment, cars, humans, plants, and as an added bonus could also be used to cook food.

Secondly, the 'mat' device uses induction (basically it's one end of a transformer). As such objects to be charged must have their charging interface very close to the charger (basically direct contact). Also, an open AC inductor like that will couple indiscriminately with any conductive material, and as such would function as an induction stove unit (put an iron pot on it and cook) and would have rather bad effects on any processors or other sensitive electronics which don't have an interface to catch the energy. While it may be 'wireless', you still need a wire to the base mat and then objects have to be in direct contact with it. IMO that's only modestly better than having a wire going directly to the thing to be charged. The main advantage is that with a largish pad you can charge multiple things universally with only one wire total. AeoniosHaplo 21:02, 18 December 2006 (UTC)

[edit] Factual Errors

Anyone can demonstrate that energy can be "sent" without a direct connection by simply touching the ends of a wire, briefly, to the ends of a small battery. Hold the wire near a compass needle while you do this and you'll see the compass needle twitch. It takes energy to make something move, so you've transmitted energy wirelessly. Well, at least without touching the compass with the wire!

Electric current induces a magnetic field. The reason the compass needle deflects is NOT due to "wireless current transmission" but merely due to the magnetic field created by short-circuiting the battery. In fact, this is an example of WIRED current transmission -- NOT wireless.

--Eibwen 18:54, 12 April 2006 (UTC)

The reason the compass needle deflects is NOT due to "wireless current transmission" but merely due to the magnetic field created by short-circuiting the battery.

It's an example of wireless energy transfer, though... — Omegatron 19:02, 12 April 2006 (UTC)
How about to use the term "electromagnetic waveforms": Wireless energy transfer (by definition) is the transfer of electromagnetic waveforms (energy) without conductive wires. - The compass example is not wrong: it is a single induction pulse with no frequency (unless it is repeated), but with dE/dT paramters (flux/energy potential change over time). The examples need to be formulated better (probably in a table), and by one or two sentences. Probably it is not required to explain all details of Tesla's research, if it is already included in the Tesla article (means it is possible to shorten the passage). However, it does not bug too much to stay like it is. I remember it on my todo list (from suggest bot). Yy-bo 12:13, 5 June 2006 (UTC)


I have the following issues, though haven't read more than the start of the article. Just thought I'd share: 1) The explanations sound like something off a textbook, but not an encyclopedia, unless proper editing condenses the rest of his explanations into a "for example" paragraph --nothing more or this will be seen as POV. 2) I agree with Eibwen but not Omegatron. I just read the first paragraph knowing full-well the effects of conspiracy theorists and protoscience on this topic. The compass example, as particle physics teaches us is not a proof of transmission, by far. It merely shows how electricity and magnetism influence objects. 3) Wireless energy should be seen as protoscience, since it is young and hasn't been experimentally falsified AFIK. For similar controversy on the topic, look up the talk pages on Randell Mills who proposes Hydrinos in ways that pull credibility away from Quantum Physics and the scientific community --seems that scientists are banded against him while enthusiasts with no proper training like the concepts in equations and tests too grand for to verify without the proper background. Tesla himself was controversial and linked to occult information and apparently has something conspiracists like. Fractaltiger 08:05, 22 July 2006 (UTC)

Actually, there is sample analogy a few links away, copied verbatim as an example of how the first section should read to be less colloquial. The article is on the Transformer, section 'An Analogy':
The transformer may be considered as a simple two-wheel 'gearbox' for electrical voltage and current. The primary winding is analogous to the input shaft and the secondary winding to the output shaft. In this analogy, current is equivalent to shaft speed, voltage to shaft torque. In a gearbox, mechanical power (speed multiplied by torque) is constant (neglecting losses) and is equivalent to electrical power (voltage multiplied by current) which is also constant.
Hope it helps.Fractaltiger 08:45, 22 July 2006 (UTC)
It is obviously a form of energy transfer. The compass needle moves against its inertia, which requires energy. You are supplying that energy from a battery. The energy was transmitted from your loop of wire to the compass through the wire's magnetic field.
As an analogy, pick up a stick and push the compass needle with it. You've just transferred energy from your hand to the compass needle through the stick. This would be "stick energy transfer", no?
Since there is no physical object connecting your loop of wire to the compass needle, and you are transmitting enough energy to make something macroscopic happen, this form of energy transfer is more interesting than sticks or radios (which send just enough energy to transfer information). But they are all the same thing; transferring energy from one point to another. — Omegatron 13:57, 22 July 2006 (UTC)
Omegatron, I expected no less of a refute to my comment :) So here is the counter-refute I had prepared. Bear in mind that this is a subtle part of an unresolved dispute in physics. See the very last paragraphs of this google search result: If in an electromagnetic field you expect a transfer of energy, with particles moving back and forth between the compass, the battery and its cables, there should be a particle delivering energy with gravitational fields too. How else can an object move in outter space with forces applied to it by stars millions of miles away, such as our sun? Worse yet, the forces seem to "act" instantly, defying the limits imposed to this whole proposal of wireless energy transfers by the speed of light itself.
How is it different from electromagnetism, since elementary particles such as photons and electrons are thought to be needed for electromagnetic energy transfers, yet seem to be a side effect of something science can't quite grasp. I re-read my posts and haven't yet stressed my point (I believe it to fall within modern science's own): The presence of the magnetic field per se is affecting the compass in the same way as the presence of the Earth is affecting the moon's orbit; no energy is transfered for this to happen --it just happens. It'd be fine if I were wrong about the particular example in the article. The entire field of the article is not mainstream. As a result, I will not be contributing ideas to the it due to my POV. You don't like seeing pseudoscience articles altered merely from people's preconceptions, and I see this as evidence that my discussing the subject could be straining. I won't go far in making more points about topics that baffle even the pros. Cheers! Fractaltiger 02:01, 24 July 2006 (UTC)
I don't understand your objection. The compass needle is being moved by the wire's changing magnetic field, so the energy is being transferred by the electromagnetic field (or by photons, depending on your perspective, no?) Wireless energy transfer is limited to the speed of light, as it is carried by electromagnetism. Did I say otherwise? This is especially obvious when you're using lasers or microwave beams as the method of transfer.
I believe gravitational waves travel at the speed of light, too, but I don't see what relevance it has to this subject. — Omegatron 14:06, 24 July 2006 (UTC)


Tesla was essentially proposing establishing an inductive field in the Earth's ionosphere, as created by pulse transmissions from a central tower which would then be tapped by remote receiving stations. ...The practical question of billing customers, even if we imagined such a ubiquitous system realized, is how could anyone prevent unauthorized usage by freeloaders dipping their cup into the stream?
Your graviton analogy is merely begging the question throughout, since as of yet there has not been any observation of the hypothetical gravity carrier particle, nor a quantum theory of gravity or a GUT, any of which are central to your comparison. To date, the most successfully inclusive mathematical model towards unification is string theory or its derivative M-theory, both of which dispose of point particles altogether, but both currently remain untestable mathematical abstraction requiring higher-dimensional spacetime. (By the way, the moon is kept in orbit by the mass of the Earth actively distorting spacetime; mass is energy; its effect is responsible for orbit. Your proposition about gravity acting instantaneously is also wrong — see gravitational waves.(...Omegatron beat me to it.))
I fail to see how your claim that power transmission via electromagnetic induction qualifies as "pseudoscience" is in any way substantiated given that the principle has physically already been put into practice (eg., transcutaneous batteries, RF power transmission), and by your own admission you are arguing from your personal pet quantum hypotheses in invoking an unrelated strawman about gravitational force. It's even more ironic that you would then unscientifically claim "it just happens" with no attributed cause; the "influence on objects" you cite with the example of the compass needle is actively affected wholly by the experimenter's intiative. Apparently you are debating only the semantics of the word "transmission" (or all of physics itself), which is not the issue of this page's topic; the principle of wireless power transfer merely states that no hardwire linkage is required.
~ GALVATRON 16:50, 30 July 2006 (UTC)


  • Wireless energy should be seen as protoscience, since it is young and hasn't been experimentally falsified AFAIK.

What?? How do you think your mobile phone/microwave oven works (if you have one)? Also I have no idea why you mentioned hydrinos, they have nothing do with this topic. User:Jaganath 17:53, 24 July 2006

Although they're really the same thing, a mobile phone wouldn't be considered wireless "energy" transfer, since they have their own power source. That's more like information transfer. But yeah we all know they're really the same thing, just different purposes and power levels. — Omegatron 17:21, 24 July 2006 (UTC)


I would like somebody to write down the names of the people who are currently working on this field. It is very important to get that information because they can help the needy more than anyone else on the planet(I suppose so atleast!).

  • Cell phones do technically transfer radio/microwave energy, but not strictly as energy transfer. While you could build a cell phone with a rectenna, it would receive almost no power and then could not function as a cell phone. Cell phone towers aren't built to beam out usable energy, only readable signal. Also, if you wired up a cell phone tower to transmit enough energy to, say, power all the homes within the cell, you'd not only waste huge amounts of energy, but also fry every living thing within transmission range.
  • One more thing, there is nothing experimentally unverified about most forms of wireless energy transfer. Most types use induction, and rectennas (which deserve a bigger mention here) have been built and tested to be able to convert microwave energy directly to DC electricity at around 95% efficiency. It is in no way a protoscience, and you are at best confusing 'science' with 'engineering'. However, if the science works, then the engineering will work too if properly implemented, and wikipedia readily mentions future technologies and new inventions (like quantum dots) in articles.
    • Final note: Ok how is this guy intending to link complete pseudoscience with wireless energy transfer? He sounds like a 'christian scientist'. There's nothing special about most forms of wireless energy transfer (except for the evanescent wave coupling version, which would replace all wall plugs if it turns out to work) and most of the variations are based on well proven technologies like radio transmission and transformers. AeoniosHaplo 21:17, 18 December 2006 (UTC)

[edit] {{cleanup}} 18:20, 1 January 2006 (UTC)

Needs to be de-Tesla-ized and some contemporary stuff added. --Pjacobi 18:20, 1 January 2006 (UTC)

Agreed. — Omegatron 16:59, 7 December 2006 (UTC)

I want to no how a beam of energy can strike the earth like a lightning bolt magnet energy does not travel at the speed of light because light is not constent magnetic energy is

[edit] Tesla is cool.

Keep Tesla in the article please.

I'm not sure what you mean by de-Teslaized, Pjacob. Tesla, who invented AC power transmission, was a pioneering thinker in the area of wireless transmission, whatever you think of his results. The article as it stands is overly dominated by Tesla information, which needs summarizing by someone who knows what they're doing. Looking at the size of the article on Heinrich Hertz today (Mar 2006), I can see that there's a whole lot of work that needs development, summarizing and scoping in the area of historical EM technology application. Twang 02:32, 19 March 2006 (UTC)

[edit] No, but clean it

Tesla was the main proponent of wireless energy transfer (usually by microwave or induction) and should be included here. However, the giant slab of tesla needs to be cut down and the archaic text removed. It reads more like an 1890s article written by some Tesla occultist than a wiki article. There's some interesting information on his 'wireless energy transfer' mechanisms, but they need to be extracted and clarified without all of the bulky nonsense surrounding them. --Haplo 24.98.124.237 08:54, 18 December 2006 (UTC)

It reads more like an 1890s article written by some Tesla occultist than a wiki article.

Exactly. — Omegatron 15:39, 18 December 2006 (UTC)
Is it just me or does tesla's energy transfer idea sound a whole lot like shooting lightning long distances? AeoniosHaplo 03:30, 19 December 2006 (UTC)

[edit] BBC News / resonant MIT technology

UPDATE on subject... Has anyone seen [1]to qoute from below "Me don't know physics so I leave this to someone who is more knowledgeable." --Vladimirko 13:03, 8 June 2007 (UTC)

Can someone incorporate this article[2] from BBC. Apparently, there is a way for commercialisation of this technology. Me don't know physics so I leave this to someone who is more knowledgeable.Vapour

Just saw this, too. Of course the news articles just hand wave everything and don't explain how anything actually works. The actual paper is here. I skimmed through it and it's a little over my head... — Omegatron 18:30, 15 November 2006 (UTC)
It appears to my (nonexpert but educated) eyes to use higher-order multipole moments and resonant devices in the gigahertz range to acheive power transfer. This is a type of coupled osccilator. Looks promising, if the issues of high-freqeuncy power conversion could be handled. - JustinWick 21:26, 15 November 2006 (UTC)
I don't understand the difference between this and a transmitter that radiates equally in all directions. I'm not grasping how it can selectively send energy in one direction but not the others. Something to do with near and far field? — Omegatron 21:47, 15 November 2006 (UTC)
Yes. If you read about higher order moments, you'll find that they don't radiate, and they are spread out unevenly. Even an ordinary dipole moment (the mode which does radiate) is hardly isotropic (a true isotropic radiator would be a wonderful device to have, but physically impossible to create under current theories). Anyways the power is "transmitted" in the form of waves that don't radiate (can't really "leave" the source as they are bound, sorry this is a bit of an oversimplification and bound to be slightly inaccurate, pardon the pun). A lot of devices, like transformers transmit energy in this way. This is just a fancy way to make long-distance transformers. Still very cool IMHO - JustinWick 09:12, 7 December 2006 (UTC)
I think I get the idea now. The near and far field article needs some work, by the way. You sound like you could help. See Talk:Near and far field. — Omegatron 16:21, 7 December 2006 (UTC)

I showed the BBC article to my Engneering friend who deal with microwave. He says that the article makes no sense. Resonate or not energy will hit human in the room which isn't good. Moreover, it is extremly inefficient way to transfer energy if what BBC article say is true. I will show the original paper to him and see what he say. Vapour

It's not efficient, however I doubt that's the main intention of the system - portability is much more important than efficiency for many low-power applications. As for the human in the room, I'm not sure how much that will affect it - see if you can get your bud to find a reference w/ the dissapation level of EM fields at various frequencies interacting with human bodies. I haven't done any of this stuff in a while, however I've transmitted at frequencies close to this (6 Mhz is 50 meters, I was on 40 at the time) with reasonably high power setups, and I never noticed any internal heating, which would be expected if there was significant interaction. - JustinWick 09:12, 7 December 2006 (UTC)
You are surrounded by transformers that are coupling 60 Hz into your body all the time, with no noticeable problems. I can see how this would be similar. — Omegatron 16:21, 7 December 2006 (UTC)

--: No, neither the BBC article nor the MIT article are correct. It does not at all work like a transformer, despite what they are feeding the public, a transformer like that would not have strong enough magnetic coupling and would waste energy. The actual mechanism behind their 'wireless energy transfer' uses two short circuited resonant radio (although it can work with any light) waveguides. The waveguides produce evanescent waves which do not carry energy, but can affect other nearby waveguides allowing the EM radiation to tunnel from one waveguide to the other (from the base station to the wireless receiver) which can then be rectified into DC electricity. See the wiki article on superlenses, evanescent waves, and evanescent wave coupling (I believe) for more specific information and links to better resources. Note that a negative refractive index material could massively boost the range and coupling for such a system. See the articles for the reason for that as well. --Haplo 24.98.124.237 09:12, 18 December 2006 (UTC)

On the contrary, it works exactly like a transformer. Evanescent fields are the electric and magnetic fields of the nearfield region surrounding any material or substance which interacts with electromagnetism. Evanescent waves are non-propagating in that they are "emitted" during 1/4 cycle by an electric current or a charge-separation, and are then re-absorbed during the next 1/4 cycle, only to be emitted again.
Partial reflection can accomplish this, but so can coils or capacitors. If you apply AC to a simple loop inductor, the evanescent wave is the expanding and contracting b-field surrounding the inductor. One simple example of evanescent wave coupling is seen whenever EM energy is transferred between the two plates of a capacitor. Note well that light and radio waves are the same thing. You say that evanescent waves don't apply to transformers? That's exactly the same as saying that Maxwell's Equations apply to transformers but do not apply to the EM fields involved with total internal reflection!
When we say that evanescent waves do not carry energy, we actually mean that the EM energy vector is oscillating, with no overall energy flow. The effect is identical to "imaginary power" in AC circuitry. But evanescent waves can easily be made to carry energy. After all, that's what the 2006 MIT paper is all about. But usually such topics are called "capacitive coupling" or "inductive coupling."
However, the MIT article contains one difference between simple capacitor/coil coupling versus "wireless power transfer." They are using high-Q resonators. This is identical to a tuned-primary, tuned-secondary transformer. In this type of transformer, the coupling between the coils is proportional to the "Q" of the resonant circuits, and with high Q, even an air-core transformer will exhibit tight coupling. Which high enough "Q", the coupling remains significant even when the primary and secondary are separated by fairly large distance. --Wjbeaty 21:16, 12 January 2007 (UTC)
Both the anon and the Wjbeaty guy are the reason I bother reading these talk pages. Often they contain much more useful information (albeit in a free form) than the article itself! Thanks for helping clear this up, guys. Anyone who's been using their physics degree more recently than I care to comment further? - JustinWick 18:57, 22 January 2007 (UTC)

[edit] Units??

Just noticed that most (if not all) of the units in this article are in miles, not SI units (as stated in the manual of style) - should these be changed? (I was going to do it myself, but I wan't 100% confident it was the right thing to do) Rarosalion 04:05, 21 November 2006 (UTC)

They should be changed unless the original measurement was specifically in miles. Like, if it says "Tesla created a device 100 ft long", you should not replace the 100 ft, but add a metric conversion instead: "Tesla created a device 100 ft (30 m) long" — Omegatron 17:01, 7 December 2006 (UTC)

[edit] Lasers, IR Remote Controls

Not that I know what I'm talking about, but if light is electromagnetic energy aren't things like an infrared remote control, or a "solar powered" (meaning desklamp powered) calculator actually wireless energy transfer. And maybe there's some kind of use of lasers to power something remotely as well (one hears of ideas to launch rocket ships with a laser ground station).

If so perhaps there should be a section on "Visible and Near-Visible Light Wireless Energy Transfer". —The preceding unsigned comment was added by 75.6.238.72 (talk) 11:29, 23 December 2006 (UTC).

There's already a section for that, although technically a solar calculator isn't wireless energy, but if you use a desklamp to power it then it is, sort of. If you're using the sun, then you don't control the power source, but a desk lamp is an artificial power source and thus counts. Oddly and very badly, but I guess it works. I already mentioned the space ship thing by the way. AeoniosHaplo 13:51, 23 December 2006 (UTC)

An infrared remote control is wireless information transfer. The physics are similar, but the application is different. Your remote control isn't providing power to run the TV; it's just sending information to it. I tried to change the intro to clarify this. — Omegatron 20:42, 12 January 2007 (UTC)

... and it has apparently been changed by User:GLPeterson to say "Such systems can be used for the transfer of either information or power", which is wrong. — Omegatron 20:43, 12 January 2007 (UTC)

[edit] an easy to read 'can't do' section is needed.

the occasional reader will ask why can't one power electric cars from a distance or sth. --Leladax 09:30, 9 January 2007 (UTC)

Yeah, that would be great. I've read a lot on Tesla now, and the documenting of his Col Springs experiments with wireless energy transfer sounded hugely promising. I've Googled for this with 'problems', but haven't found any discussion on it. What was the major problem with conducting electricity through the earth in this way? The Wiki article on standing waves references his discovery of these from a thunderstorm hundreds of miles away, and his counting on these as proof that waves could be broadcasted this far. Is this not the case? It's hard to believe we've gone from this in 1899 to a Splashpad in 100 years, seems like little progress. ;-)

[edit] Power beaming

Merge or not? I support the merge. — Omegatron 23:54, 19 January 2007 (UTC)

Do it. GPeterson 00:15, 21 January 2007 (UTC)

[edit] Wireless energy transfer is NOT information transfer

Maybe some examples will make this more clear:

Wireless energy transfer
  • Microwave rectennas powering model airplanes
  • Rechargable toothbrushes being charged without a direct connection
  • Charging mat for portable gadgets
  • Artificial heart and other bionic devices
Wireless information transfer
Wireless power and information transfer

— Omegatron 23:54, 19 January 2007 (UTC)

I agree with you that wireless energy transfer is not information transfer. On the other hand, wireless energy transfer CAN be used to transmit information from one point to another, and it is okay to say so. Here are the words of a pioneer in the field of wireless energy transmission.

"On my return to New York [from Pittsburgh] the next year, that was early in 1889, I engaged a laboratory at 175 Grand Street, close to Center Street. . . . I had at that time already perceived enough to get the idea that energy could be transmitted without wires. It was of no consequence to me at that time whether it was to be used for telegraphy, or telephony, or power transmission. I was on the problem of transmitting energy without wires; and as it is my custom always to analyze scientifically every problem that I undertake to solve, I devoted a great deal of thought to how to attack that problem, and the following crystallized out. . . ." Nikola Tesla on wireless telegraphy, telephony and transmission of power, 1916

Wireless energy transfer and wireless power transfer are not synonomous terms. If this is really a problem for you, I suggest that you create an encyclopedia entry entitled "Wireless power transfer" or change the title of this one. GPeterson 22:49, 20 January 2007 (UTC)

This article is about transmission of energy for the purpose of supplying power to otherwise unpowered devices things. Radio is the article about transmission of energy for the purpose of transferring information. They are distinct applications of the same physics concept. Stuff about radio, broadcast,and telecommunications needs to be moved into the appropriate article.
I view this article as simply being about the transmission of energy.
An article titled "wireless power transfer" would be a sloppy use of terminology, since power is defined as the rate at which energy is transferred. You can transfer energy, but "transferring the rate of energy transfer" doesn't make much sense. Wireless power transmission already exists, but is a redirect to this article, since they would cover the same topic and "Wireless energy transfer" is the more correct term. If you need to think of this article as if it were titled "Wireless power transmission", to differentiate it from information transfer, then please pretend so. — Omegatron 00:08, 21 January 2007 (UTC)
The present title is just fine. . . . GPeterson 00:29, 21 January 2007 (UTC)
FYI, other EM data transfer includes optical, microwave, IR, and conceivably higher band (UV/X-ray, and perhaps some day gamma radiation) transfer, and ELF of course. Having EM data transfer implied to be synonymous w/ Radio is preposterous, as I'm almost certain that optical alone transfers more bits per day because of human technology than radio. - JustinWick 18:41, 22 January 2007 (UTC)

[edit] From "Evanescent wave coupling" onward

None of this has been proven or demonstrated and it appears that it will be a failure just like it was 80+ years ago. The inverse square law still holds, even at MIT.

There has been "zero" mention of it in any "peer reviewed" journal.

There is a direct challenge here (prize unclaimed):

http://tech.groups.yahoo.com/group/wireless_energy_transmission/

The direct references are over 80 years old and none of the patents or others ever came to fruition...

Those guys at MIT had better spend ten minute wiring it up for a demonstration about "now", or start thinking of "excuses"... "Big energy companies are blocking our work to save the economy" has been a popular "free energy" excuse for the last 30 years...

"Wardenclyffe was not completed due to financial difficulties" - As in, the financial backers realized it was a complete disaster...

The last parts of this article is pseudoscience.

63.229.238.57 01:39, 11 February 2007 (UTC) Gandolf

Do you really mean pseudoscience? Protoscience might be a better term for these cases. GPeterson 23:53, 16 February 2007 (UTC)

[edit] Through the Earth

This article about electricity conducted through the Earth is suspicious, and makes claims which are not supported. For example, it defies "ohms law". It states that the electrical resistance of the Earth is "negligible" which is false for DC current. Electrical resistance drops off for AC current and varies with frequency, but the author does not provide any numbers or the equations to explain the impedance claimed. In fact he/she does not even specify what the resistance (impedance) actually is. That section of the article needs to be improved or removed. Charles 20:25, 24 February 2007 (UTC)

-Given the massive cross-sectional areas involved, the impedance of earth-transfer is very close to zero. Impedance is proportional to the distance and inversely proportional to the cross-sectional area of the conductor. Take a series of cross-sectional slices, tracing the path of the current through an earth-conducting circuit. The current density is only high at the nodes, whereby impedance really matters. If the earth circuit is sufficiently coupled, you're suddenly talking about tens-to billions of square metres of conductor cross section. Whereupon impedance becomes negligible. Earth-return AC power is quite commonly used for remote farms and installations, and the impedance of the return line is only really dependant on the coupling of the nodes at each end. 210.9.200.35 04:14, 3 April 2007 (UTC)

[edit] Major Rewrite - Do not panic!

Greetings folks, I did a major reorganization of this page, I did not delete anything (even things which look a little suspicious), but somethings have been moved around, and I added some new sections and subsections, and a lot of additional content and references. I hope you all like it, I believe it is a major improvement, although I say so myself. Charles 21:00, 24 February 2007 (UTC)


[edit] Spark Plugs

Omegatron you are incorrect in this comment " (→Air - power isn't "jumping between the electrodes"; it's being converted into other forms of energy like light and heat. electrical energy and electrical current are NOT the same thing.) " In a spark plug the power is transmitted between the electrods, current flowing from the positive electrode, through the air gap into the negative electrode. Some of the power is dissipated as light and heat, but there is a current, it is not all dissipated.Charles 23:46, 24 February 2007 (UTC)

Sorry, but that's not correct. Electrical current, electrical energy, and electrical power are all distinct concepts. Please read about them.
To summarize: current is the flow of electric charge, which is usually in loops, energy travels from the source to the load, and power is the rate at which that energy travels. — Omegatron 23:56, 24 February 2007 (UTC)

OK, so I see we are just fine tuning terminology, we agree on how the spark plug works. I well understand all those different terms (B.Sc. Physics (Lon) 1977).Charles 01:40, 25 February 2007 (UTC)

[edit] Applications

The applications section should be dissolved and applications for specific types should be in the section about that type. In other words, powering gadgets should be mentioned in the evanescent section, artificial hearts should be mentioned in the induction section, electrolasers should be mentioned in the air conduction section, etc. It's confusing and poor form to have the applications of each technology in a completely different section from the technology itself. — Omegatron 00:28, 25 February 2007 (UTC)

[edit] Reformatting

I agree that the whole article is poorly organized and the applications and methods could be combined. At least I made a start on it, I am open to improvements.Charles 01:05, 25 February 2007 (UTC)

--

I am willing to take a shot at this if you like. Or let me know if you would prefer to do it. Charles 01:11, 25 February 2007 (UTC)

Phew! I rearranged it.  :-) — Omegatron 02:26, 25 February 2007 (UTC)

[edit] Cardiac energy transfer through tissue

Omegatron, you do not know what you are typing about here. I have worked with cardiac implants for over two years, and I know in detail how they work. They transmit energy through human tissue, specifically the heart muscle. The implants do NOT use induction for the stimulation. I have worked on measuring the impedance (electrical resistance) of the heart tissue to optimize the power usage between the electrodes.Charles 01:05, 25 February 2007 (UTC)

Here is a detailed description from the world's biggest manufacturer of pacemakers, describing how they work in some detail. I hope this helps clarify. The amount of energy delivered is relatively small, they are brief pulses of DC current.

http://www.medtronic.com/servlet/ContentServer?pagename=Medtronic/Website/StageArticle&ConditionName=Bradycardia&Stage=Treatment&Article=brady_art_how_pace_works


Charles 01:36, 25 February 2007 (UTC)

Yeah, but how is that relevant to this article? The important aspect for this article is that the energy the devices use to function is transmitted to their rechargeable batteries through induction coils. — Omegatron 02:26, 25 February 2007 (UTC)

No wrong again! The batteries are NOT rechargable. Where are you getting this stuff? Induction pickup is used to upload software and download history data. There is no induction involved in the power side, the battery power delivers DC pulses directly into the heart tissue.Charles

The batteries in cardiac implants last several years. The physician keeps track of the charge state during follow-up visits, and before they are depleted they issue a warning. They are then surgically removed and replaced with a new device, this is an outpatient procedure.Charles 02:58, 25 February 2007 (UTC)

Please learn about transcutaneous energy transfer before making further edits to the article. Here are some links:
No one is using tissue conduction to transmit energy. It should be obvious to anyone that this would be quite harmful. Any device that transfers energy to devices inside the body is going to use induction. Skin conduction is used to send low-power signals, like in personal area networks, but that's information transfer, not energy transfer.
Stimulating the heart through tissue conduction has nothing do with wireless energy transfer. — Omegatron 04:52, 25 February 2007 (UTC)

WRONG! You are confused between apples and oranges. The links you posted all relate to the artifical heart only, and I have accepted all along that those are correct for the Artifical Heart ONLY. But the Pacemakers and Defibrillators operate on completely different principles. Tranmission of energy through tissue is indeed dangerous, and can cause damage if the current is too high (this is not a game for amateurs, do not try this at home). Nevertheless, it is precisely the principle on which pacemakers and defibrillators operate, and believe me getting FDA approval for these devices is a major undertaking. The size of the pulse supplied is large enough to stimulate the electrical response of the muscle tissue, but small enough so as not to cause tissue damage. You really have to know what you are doing to get the pulse delivered correctly. I have already posted link from Medtronics which you apparently refuse to read. Here it is again: http://www.medtronic.com/servlet/ContentServer?pagename=Medtronic/Website/StageArticle&ConditionName=Bradycardia&Stage=Treatment&Article=brady_art_how_pace_works

Also, looks at these FDA links:

This is a nice overview article of both pacemakers and defibrillators: http://www.fda.gov/bbs/topics/CONSUMER/CON0279b.html

Then more info on pacemkaers:

http://www.fda.gov/bbs/topics/ANSWERS/2001/ANS01100.html

http://www.fda.gov/cdrh/pdf/P010015b.pdf

Pacemakers can go wrong, and can than become harmful, in those cases product recalls are issued, such as this one: http://www.fda.gov/cdrh/recalls/recall-071805.html

Charles 08:16, 25 February 2007 (UTC)

But that has nothing to do with this article. This article is about transferring power wirelessly to electrical devices. I've said this a million times, and I'll say it a bunch more so you get the point. The only reason bionic implants should be in this article is because power is transferred to some of those implants wirelessly, (instead of a wire going through the skin or using permanent batteries). The artificial heart and (at least a few) pacemakers and internal defibrillators are powered or recharged wirelessly. This energy transfer is always through induction, not conduction. — Omegatron 20:40, 25 February 2007 (UTC)

[edit] Power Levels

The power levels for External Defibrillators are much higher and the voltages much higher than for implantable devices. That is why paramedics yell "CLEAR!" before delivering the pulse (have you watched any ER TV shows?). The high voltage penetrates the high resistance of the skin using conductive pads, and deliver 150 Joules (for adults) of electric current passed directly through the chest cavity.

Here is an FDA article on one model (for children) which presents some numbers (50 Joules for children versus 150 Joules for adults):

http://www.fda.gov/bbs/topics/ANSWERS/2001/ANS01082.html Charles 09:06, 25 February 2007 (UTC)

That has nothing to do with this article. This article is about transferring power wirelessly to electrical devices. — Omegatron 20:40, 25 February 2007 (UTC)

[edit] Circuit Diagram

Perhaps this will convince you, here is an electrical circuit diagram from the Wikipedia article on Defibrillator#Design.

A circuit diagram showing the simplest (non-electronically controlled) defibrillator design, depending on the inductor ( damping ), producing a Lown, Edmark or Gurvich Waveform
A circuit diagram showing the simplest (non-electronically controlled) defibrillator design, depending on the inductor ( damping ), producing a Lown, Edmark or Gurvich Waveform

—The preceding unsigned comment was added by Cfrjlr (talk • contribs) 09:11, 25 February 2007 (UTC).

That has nothing to do with this article. This article is about transferring power wirelessly to electrical devices. — Omegatron 20:40, 25 February 2007 (UTC)
Sounds good to me. So the best thing would be not to make any mention of pacemakers or difibrillators at all since they do not fit within the criteria you have defined.Charles

[edit] Disputed?

Is the article accuracy still disputed? The only contentious point I see now is the Tesla stuff. — Omegatron 02:28, 25 February 2007 (UTC)

I agree, it looks pretty good to me now Charles 02:58, 25 February 2007 (UTC)

[edit] Directed energy weapons

Can someone please explain what this has to do with this article? This article is about wireless energy transfer. Like, wireless replacements for telephone poles and power cords. It's not about shooting things with laser beams to destroy them or sending electrical currents through people to restart their hearts. — Omegatron 20:32, 25 February 2007 (UTC)

You were the first one to mention weapons, the bit about UV lasers to ionize airCharles 00:03, 26 February 2007 (UTC)

That's not an example of a power transmission device, though; it's just an example of a conductive path through the air. I don't know if anyone's actually using it to power things remotely. — Omegatron 19:14, 28 February 2007 (UTC)

[edit] Short distance wireless energy transfer

I didn't add anything to the article itself because it might come off as spam—this is just a heads-up. I just read in Popular Science (March 2007) that Pennsylvania-based Powercast is (supposedly) developing wireless "power strips" to debut this year. This is one of the most concrete announcement I've read about in the media wireless energy transfer.--gwc 18:15, 28 February 2007 (UTC)

Powercast is already in the article. It's just low-power RF from what I have read. Like a trickle charger with lots of wasted radiated power. — Omegatron 19:15, 28 February 2007 (UTC)

[edit] Right to fork

Notice: A dispute has arisen between GLPeterson and Omegatron regarding the scope of the article "Wireless energy transfer." Omegatron maintains the article should include only information about systems for wireless power transmission. GLPeterson maintains that in addition to wireless power transmission the article should include information on systems for wireless communications, remote sensing, and also about systems which combine two or more of these into a single system. In order to press forward with development of the more inclusive article GLPeterson has invoked his Right to Fork (see http://www.usemod.com/cgi-bin/mb.pl?RightToFork ) and started a new article titled “Wireless energy transmission.” Omegatron has repeatedly vandalized this new article by replacing the text with a redirect to “Wireless energy transfer.” Best regards, GPeterson 18:36, 1 March 2007 (UTC)

We already have discrete articles about Wireless energy transfer, Wireless communication, and Remote sensing. If you'd like to merge them, you can propose that, but you'll find very little support. Wikipedia:Disambiguation explains how articles are divided up when they have similar names or similar concepts.
There is no Right to Fork on Wikipedia. Forking an article because you disagree about its scope is expressly forbidden, in fact. See Wikipedia:Content fork.
You can, of course, take all of the content from these articles and publish your own document off-site that combines them. — Omegatron 18:55, 1 March 2007 (UTC)

Dear Ώtron,

There is no Right to Fork on Wikipedia.

Pardon me.

You can, of course, take all of the content from these articles and publish your own document off-site that combines them.

Let me see if I have this right. An article titled "Wireless energy transmission" discussing wireless systems that combine wireless communications (including remote control), remote sensing and power transmission, etc. is expressly forbidden on Wikipedia? GPeterson 20:25, 1 March 2007 (UTC)

If those articles already exist? Yes. You'd have to merge them. Please read Wikipedia:Content fork; it is all explained there. — Omegatron 18:43, 2 March 2007 (UTC)

There is no Wikipedia article discussing wireless systems that combine broadcasting, wireless telecommunications (including remote control and monitoring), remote sensing, electrical power transmission, and other features into a single wireless system. This is the topic of the article “Wireless energy transmission.” This being the case, why do you keep vandalizing it? The article in its present form is not a fork, in spite of your arbitrary and unjustified designation of it as such. It is an original article on a subject that is not addressed by Wikipedia. If you truly feel it is a POV fork then you are welcome to nominate it for deletion. Any other action is entirely inappropriate. Most sincerely, GPeterson 19:38, 2 March 2007 (UTC)

Why beat your head against the wall? There are other general-reference wikis of moderate size that would welcome your well-intentioned contributions: Wikinfo and Wikiknowledge.[3]-69.87.204.228 12:04, 9 June 2007 (UTC)

[edit] Communications

Please stop adding stuff to this article about communications. It's the wrong article, as explained above many times. — Omegatron 20:49, 18 March 2007 (UTC)

[edit] Powercast

It's a newspaper article, so the science is probably garbage, but here's a more detailed description:

[4] — Omegatron 21:13, 12 April 2007 (UTC)

[edit] Tesla Effect

This is being brought up again. This "term" was deleted as a separate article, and it's now being resurrected here - WTF?? Bert 05:22, 15 April 2007 (UTC)

  • It shouldn't have been deleted as a separate article. When did that happen?
  • I'm starting to feel like all additions about Tesla to this article just be reverted, until proponents can produce good references and plausible connections to real-life technology. — Omegatron 15:31, 15 April 2007 (UTC)

[edit] Y-trcity

Read Important!!!

Actually, is is being called WiTricity.-69.87.204.228 12:27, 9 June 2007 (UTC)

Ok. coudn't find any other references so didn't know preper name. DC

[edit] rectangular waveform

"If resonant coupling is used, where inductors are tuned to a mutual frequency and the input current is modified from a sinusoidal into a rectangular waveform, significant power may be transmitted over a range of many meters."

This reference to "rectangular waveform" sounds wrong to me. I'll delete it. If you know that it really belongs, please word it accurately, and include a reference.-69.87.204.228 12:27, 9 June 2007 (UTC)