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Wireless Power Over Distance: Just a Parlor Trick?
Lucas123 writes "Companies like U.S.-based WiTricity and China-based 3DVOX Technology claim patents and products to wirelessly powering anything from many feet away — from smart phones and televisions to electric cars by using charging pads embedded in concrete. But more than one industry standards group promoting magnetic induction and short-distance resonance wireless charging say such technology is useless; Charging anything at distances greater than the diameter of a magnetic coil is an inefficient use of power. For example, Menno Treffers, chairman of the Wireless Power Consortium, says you can broadcast wireless power over six feet, but the charge received will be less than 10% of the source. WiTricity and 3DVOX, however, are fighting those claims with demonstrations showing their products are capable of resonating the majority of source power."
i mean, the amount of effort it took you to make that rock round and then roll a log over it? you could have carried 10 logs in that time. quit with the making new shit, gorg, it isn't useful at all and it isn't like anyone will ever find a way to improve on it. ...
oh, nice vette, gorg.
Back in the day, Tesla had achieved even greater success. Though if you can charge from anywhere, how can you be billed? That is what will permanently stop this type of technology.
Have they tested its ability to charge the phone of someone with a pacemaker or other medical device? Sure, it charged the phone, but he was no longer around to make a call...
... the marketing department and the vaporware wizard are trying to mess with inverse-square law.
You also have to consider the efficiency. Running a 1GW power plant just to light a 100W light bulb a few kilometers away does not seem a good idea.
Yes, it is possible to transfer power without wires - radio has been doing it for a long time (a simple crystal radio set does not need any power other than what it gets from the antenna, but you'd better have some sensitive headphones, a big antenna and a station that is relatively close). The problem is transferring a lot of power efficiently and without huge antennas.
I think these are a great idea and I would not be surprised if Apple start to support them in the future. A phone could be built with no open connections at all. Just wireless data and inductive charging. But over longer distances the laws of physics catch up with up. Obviously the shorter the wavelength the less doffraction you get over a given distance so if you direct power with a laser and convert it into electricity with a photovoltaic cell then you could easily get more efficiency over a few metres than with induction. Maybe in the future it will be considered normal to transmit power that way.
http://michaelsmith.id.au
...but, the further you go the more it resembles eating your lunch sitting on power lines.
At the one end, there is no measurable danger in charging handset on a pad charger. But do you really want to spend all your television watching hours in a room where 200 watts of power is being beamed to your TV (and 19x being radiated) from the wall to save you the bother of the unsightly cord?
If you have magnetic wave energy, you have electric wave energy, which means you have RF. You can shape the way you transmit RF energy, but there are no perfectly absorbtive receivers, and splatter is a function of distance. So at contact distance (phone on the pad) it's pretty fine.
The claim was "most"of the power gets there. Let's assume they are not full of crap. So 49% of the power is splatterd around. So your 1800 watt cordless hairdryer splashes 1730 watts around the bathroom? And people worry about .1 watt GSM transmitters in their phones?
I guess I need you to trust an A/C on this point, the extra four orders of magnitude makes a difference.
You also have to consider the efficiency. Running a 1GW power plant just to light a 100W light bulb a few kilometers away does not seem a good idea.
Yes, it is possible to transfer power without wires - radio has been doing it for a long time (a simple crystal radio set does not need any power other than what it gets from the antenna, but you'd better have some sensitive headphones, a big antenna and a station that is relatively close). The problem is transferring a lot of power efficiently and without huge antennas.
Their claims are apparently that they can achieve better efficiency than had been thought possible.
Anyone who wants us to believe differently should have independently verified proof. If you suspect parlor tricks, it's helpful to have a magician involved in addition to the scientist or engineer. "Extraordinary claims" and all that...
Or maybe a bad summary? Almost 50% loss over a relatively short distance might match the claims of "majority of the power".
The problem is inefficiency. Power drops with the square of distance. That means you need a bigass transmission source to get a small amount of power any distance away, hence why things like FM stations have 5 digit wattage transmitters.
Yes we have been able to transmit power wirelessly for a long time, no it is NOT practical or efficient. If you are enthralled with Tesla, spend some time reading some actual books on him, not just the silly piece by the Oatmeal. He was a fascinating man and worth your time to learn about, but you need to learn about him if you want to go spouting off.
He didn't invent some magic transmission technology we can't replicate, he invented an inefficient transmission technology that we can replicate, but don't, because he was not able to solve the efficiency problems (and it may not be physically possible to).
This has already been done, on few hundreds meters using big directional antenna in area where you can install wires. I just cant remember where it was.. A tv documentary I've seen 10 years ago at least. Somewhere in south America, to power some scientists observatories or alike.
If you don't make your power signal directional, most of the power is just gonna leak away into the atmosphere.
This is not how these devices are supposed to work... that is to say, this is not the same as radio. It's a near-field, not radiative, effect. Most of the power that does not go into the receiver returns to the transmitter as part of the resonant oscillation (via a collapsing magnetic field.) Some will be lost to fringing, but the percent lost to that per oscillation is much lower than the percent absorbed by a properly tuned receiver, by design.
Not that I'd advocate this for consumer use, it will still be less efficient than a wire, and I'd rather see consumers suck it up and run a wire where appropriate instead of finding yet one more way to waste energy and pile ruin on our planet. However there may be some very productive niche uses.
Someone had to do it.
Yeah and? You realize that most of the power was lost before being received over that long distance, right? Tesla didn't break the laws of physics despite what his modern-day, rabid fans would have you believe.
How was it lost? We know exactly the physics behind his transmitter. There was nothing magic about it.
They've seen people who live under high voltage power lines seem to have a higher rate of cancer
So I would think it would be possibly dangerous to come close to fields where energy is passing through your body. The more energy involved the worse off I'd think people would be. I don't tend to worry much about low energy fields like cell phones or wifi. Yet if a job powered all the computers with remote energy so I'm exposed all day long, I'd have to decline that job. No sense risking cancer for any amount of money.
God spoke to me
I'm as big a Tesla fan as anyone, but I'm also a practical electrical engineer.
Someone above already raised the end-point billing issue the utilco's will have, so we needn't bother with the bean-counter side of things. MBA's, rest easy. Your obscene profits are safe.
However, going from a theoretical ability to blast x amount of joules across an air gap to capturing a useful fraction of x without frying the adjacent wildlife and neighbors is quite another thing. As TFA points out, they seem impressed with a 10% capture rate, which to an engineer means a 90% loss of efficiency.
There is also this unpleasant fact of biophysics: sufficiently strong electro-magnetic fields, regardless of frequency, are inevitably fatal. The required grounding, shielding, etc. would be so outrageously expensive that the cost of copper wires pales.
Some science fiction does eventually become science fact. However, Thermodynamics, biochemistry, and basic engineering discipline relegate most of it to forever remaining fiction. Sorry, no Nobel Prizes here.
Scruting the inscrutable for over 50 years.
the only way to make this efficient is to make the format mandatory and exclusive, every single device must be compatable with every other, that way battery powered devices no longer need charging cables packed in, the expectation is that you have a charging mat.
no more car chargers, no more wall wart chargers, no more devices disposed of due to worn out charger connections.
make sure all are compatable, or near compatable with only variability being amperage output, clearly marked on chargers and minimum to charge marked on all devices.
Snowden and Manning are heroes.
"Wireless high power transmission using microwaves is well proven. Experiments in the tens of kilowatts have been performed at Goldstone in California in 1975 and more recently (1997) at Grand Bassin on Reunion Island. These methods achieve distances on the order of a kilometer."
http://en.wikipedia.org/wiki/Wireless_energy_transfer#Microwave_method
Why was his info "Illegally Seized " a at the time of his death and is still not known today ?
I'm not saying it was aliens....but it was aliens.
The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
"Tesla figured out how to broadcast power miles away, wirelessly, using technology available in the late 1800s. "
STOP IT. this is a false statement. Tesla went bat shit crazy, and made shit up.
Yes he was a genius and found out how to do some great stuff. Lets celebrate that and not the Bullshit myth.
I'll be impressed when you idiot can start to separate fact from fiction.
And before you replay, if such a device existed, billing would be trivial. IT's like people really ignorant of electrical engineering and Billing practices came together to fall under a conspiracy theory instead of ACTUAL THINKING about it.
There are many ways to bill, but I will sum up with an example:
I pay for sewer, yet there is no Sewer meter on my sewer line.
The Kruger Dunning explains most post on
he didn't invent wireless communication.
look up photophone (1880)
or
David E. Hughes 1889
or
Heinrich Hertz
or
Chandra Bose
One popular comic ass talks about Tesla, makes factual wrong statements about Tesla, and every self proclaimed 'nerd' starts repeating it like it's actual fact.
The Kruger Dunning explains most post on
Looked at one of the demo videos. There is a 4000watt transmitter (in middle of floor, nevermind the radiated power someone is gonna trip on it!) a few feet away from most of the stuff and i don't see 2000w worth of stuff.
Don't know how it works, don't care so much to look. I don't plan on adding a 4000watt transmitter to each room, seems like a half dozen power cords would be a bit cheaper. Not that i have any interest or hope for anything called 3D power...sigh.
But...Does the green carpet in the one vid play into it? The TV didn't come on til he touched the floor.
Wonder how good the wireless internet is 18 inches from that transmitter where he set the laptop down.....
What if i add this 4000 watt transmitter to my apartment, as does my neighbor, etc. Before we finish the complex we will enough power running to add a couple TV channels much less the recievers :O
There seems to be some confusion on this thread between magnetic resonance, which is the type of power transfer used by WiTricity and others, and radiative RF which is the radio technology we are used to. For example, received power does not fall off with the square of distance in the case of magnetic resonant systems. There are definitely a ton of challenges to this technology, but it is good to keep in mind that they are NOT talking about transmitting a high power RF signal and having it received at range. Here is a link to a paper that describes both types of systems so you can understand the implementation and trade-offs. The author's have achieved 80% efficiency over a few meters using magnetic resonance. Experimental Results with two Wireless Power Transfer Systems http://sensor.cs.washington.edu/pubs/WISP-WARP.pdf Video and other good info: http://www.alansonsample.com/research/wrel.html
The referenced paper actually describes two systems based on RF power transfer. Here is one on magnetic resonance: http://www.alansonsample.com/publications/docs/2010%20-%20TIE%20-%20Magnetically%20Coupled%20Resonators%20for%20Wireless%20Power%20Transfer.pdf
Yeah because he used some different form of physics not available in our time, right?
But...but...the Oatmeal guy said it so it must be true!!!
There are a lot of hard engineering problems to overcome, even if the system was efficient... For example, a second resonant load nearby severely de-tunes the system, antenna mounting considerations are of supreme importance (good luck putting one on a laptop full of metal), and antenna alignment is absolutely crucial! The whole WiTricity concept might be sound in theory, but the engineering challenges are monumental.
Chapter 4 of the ARRL Handbook has a section on coupled resonant circuits. The critical coupling coefficient is equal to the inverse of the geometric mean of the loaded Q's of the two resonant circuits. With the coupling coefficient dropping with the 6th power of the spacing, once the spacing significantly exceeds the radius, the required Q's really quickly become unrealizable.
A Shadeless room is a brighter room.
no more car chargers, no more wall wart chargers, no more devices disposed of due to worn out charger connections.
However this problem could be fixed without ever leaving the wired space. To some extent, it is already being fixed with USB, but for higher power devices, PoE/PoE+ might be a good thing to encourage, even for non-networked devices.
Now if we could just get them to stop changing the damn connectors all the time.
Someone had to do it.
I could build a (very expensive) field generator with some funky shaped field with much of the flux passing through some point six feet away. Only problem is, you'd have to stand in that exact spot.
I agree that these products are BS and/or a waste of energy. If you just think about field lines, either they all pass through your phone or they don't. If they cover a wide area, clearly most of the possible flux is not hitting your phone. Fields 101.
I suppose you could install many field generators and have them test if there is a resistance associated with a receiver. But I don't see how you could do this and have high efficiency several feet off the ground. The geometry just doesn't work, IMO.
.....? So how many of Heinlein's novels did you have to read before finally concluding his non-cursing creeps you out? Was it a growing sensation, a feeling of unease slowly building inside you, nibbling away at your very soul as you shifted restlessly on your seat, brow furrowed in discontent? I can just imagine you sitting there with feet kicked back in your overstuffed blue armchair by a cozy fire, suddenly shooting straight to your feet when it dawns on you: "Holy shit! Now I realize what's been bugging me the fuck out about this crazy ass novel! It's been six chapters now and not the first fucking sign of a cussword. I'm starting to think the guy is a goddamn prude, honestly. There sure as hell better really be something lewd or crude in this incestuous intra-family love triangle / murder he's currently setting up, or I just might throw this book across the room......before hurriedly snatching it up and continuing reading to confirm that he did indeed not curse once. By God if I have to suffer through every single one of his bullshit Puritanistic preachings to get my satisfaction I will! And if I don't get it.....? Well I suppose Heinlein is a really fucking creepy guy."
Personally, I think the Tesla worship among geeks has gotten WAY out of hand in recent years. Yeah, I know the Evil Rich Guy Edison vs. the Poor But Plucky Tesla makes for a great literary narrative. And I don't discount the guy's work (particularly with alternating current, which he was right to argue for over DC as a practical means of long range electrical transmission). But he wasn't a god, he wasn't 100 years ahead of his time (as some recent hyperbole would have it), he didn't invent anything which subsequent engineers haven't since replicated and improved on, and he didn't certainly didn't invent EVERYTHING (the list of claimed inventions seems to get longer every year, in spite of the fact that he remains decisively dead).
I think we do him an honor to recognize his REAL work. But we do him a dishonor to exaggerate, or even mystify, his accomplishments.
SJW: Someone who has run out of real oppression, and has to fake it.
I'm waiting for my apology.
#fuckbeta #iamslashdot #dicemustdie
Sending out power for wireless charging is inefficent, but the radio and TV stations are already sending out tens of thousands of watts. Also your wifi is already transmitting. Absorbing that energy 24/7 would at least help keep a phone or some low power device charged, so why not.
The problem with Tesla's system is the frequency on which it operates. 10 Hz has a wavelength of 34.73 meters. Properly receiving power at that frequency requires an antenna sized to match. Needless to say, it's not going into a handheld device. Tesla intended his system to be used in relatively large scale fixed installations. You could power your house with it, but the individual pieces of equipment in the house would be wired to the receiver. So yes, in theory his system could eliminate the grid as we know it and that does indeed address "power over long distances" as the headline does (really long distances). However, it's solving a different problem, that of very long distances using very large equipment, rather than the handheld gear over tens of feet as the articles are arguing over.
The magnetic field drops off rapidly with distance. At very close range, south American monkey in treetops near the line during winter range, there is so much induction that there is enough heat to be felt so the monkies kept warm. A field strength that high was the cause of many miscarriages among women that used poorly shielded RF plastic welding machines in the USA in the 1950s-60s. You've got to be almost close enough to worry about arcing to get that much RF from a power line, but there are known problems. Where things get odd is people insisting that twenty metres from a line is a problem, when at that range you'd be getting a tiny percentage of what you'd get from an electric blanket.
That's true, but the poster went off the deep end babbling about how what Tesla did was a myth, and it's crazy pseudo-science, and blah blah blah. Tesla succeeded in transmitting power over long distances and low loss rates wirelessly, that's historical fact. It may not work well with mobile devices, but I never claimed it did. I simply pointed out... it's not a new idea, or a new technology.
#fuckbeta #iamslashdot #dicemustdie
These are inductive near-field communication devices. They use a linear transformer (two circuits with self inductances, and a mutual inductance), with capacitors, to transfer power to a load. The capacitors cancel out the self-inductances of the transformer. There is no magic. Greg Durgin of Georgia Tech has a good lecture available on Youtube, that goes over the circuit analysis of such systems : https://www.youtube.com/watch?v=qwEl5Up4AIU&feature=plcp
The range of these systems is quite poor.
I could build a (very expensive) field generator with some funky shaped field with much of the flux passing through some point six feet away. Only problem is, you'd have to stand in that exact spot.
You need a flux capacitor.
I looked into that article and the guy who wrote it. The quote you're quoting comes from a book he wrote himself (although the quote is from a chapter written by some other guy.)
Unfortunately I couldn't find an online reference however, so it's impossible to know just how the measurements "Dr Van Voorheis" mentions were made. So far I've had a hard time to find any examples of people who have actually reproduced the large scale effects that Tesla claimed to achieve.
If you look for the author of the article (Thomas F. Valone) you find some YouTube clips where he's presenting a talk about UFO power sources. And he seems to be part of a MUFON which is apparently a group of UFO hunter enthusiasts. Now there's nothing really wrong with that, but it does mean that I'm not likely to take his claims at face value. And even he doesn't claim that the Tesla stuff is real, he only quotes other people (mostly Tesla himself).
Meanwhile you have an article at IEEE (http://spectrum.ieee.org/green-tech/mass-transit/a-critical-look-at-wireless-power/0) which seems to support the common understanding of wireless transmission of power. Basically that you can transmit power on roughly the same distance as the diameter of your coils. So a "charging pad" works, but powering a ship on the other side of the Earth doesn't.
To summarize I have to say that I'm quite convinced that if Telsas "World Wireless System" would have worked the results would have been reproduced today. The economic benefits are way to large for it not to. I'm sure the military would have loved to have remote powered drones and stuff like that if it was possible.
Marconi and Braun, Nobel prize winners. Tesla was like 10 when they did this.
Is tree bark made of chocolate, in this fantasy world you inhabit?
Just curious...
An enigma, wrapped in a riddle, shrouded in bacon and cheese
he didn't invent wireless communication. look up photophone (1880) or David E. Hughes 1889 or Heinrich Hertz or Chandra Bose
Theoretical experimentation != invention.
If it did, I would be considered one of the "inventors" of anti-gravity.
One popular comic ass talks about Tesla, makes factual wrong statements about Tesla, and every self proclaimed 'nerd' starts repeating it like it's actual fact.
Or, one popular comic ass talks about Tesla, and every self-aggrandizing asshole and his brother comes out of the woodworks to accuse everyone else knowing precisely dick about the topic.
Get over yourself, dude - some of us were Tesla fanatics long before there was such a thing as shitty web comics.
An enigma, wrapped in a riddle, shrouded in bacon and cheese
At this point though, the volcano powerplant makes more sense.
dude, you forgot the link to your Kickstarter page!
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Isn't effective data rate directly correlated with power levels?
So yelling at grandpa really does make him understand quicker?
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Next you're going to try to tell us that Telsa didn't invent the teleporter! [*]!
[*] granted, it was more a remote matter duplicator than a true telporter, but there's ways of dealing with that.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
If it's an isotropic antenna radiating the power, then yes... the amount of received energy decreases as a square of the distance. But tesla wasn't using isotropic antennas. In fact, he was basically using giant coils to induce current flow in the Earth's magnetic field. By coupling it to the already-existing magnetic field, he could transmit power over very long distances at low losses... but it required a very low frequency (7.8hz) and a massive amount of input energy to run the process. It was definately not a mobile technology, and it depended on having a massive several-story tall coil as a receiver, again due to the very low frequency above.
You're not going to be powering drones using Tesla's technology... but you could transmit power from coast to coast rather than just regionally using our existing grid.
#fuckbeta #iamslashdot #dicemustdie
it has to be, anyways, so why not. if the charging field was harmful to other devices nobody would install them. (forget to shut off your car charger, nuke all your electronics) so why not make them using the same standards? nobody would fire up the car coil to charge a cell phone, but it might be useful for corporate users to have an IT closet with a car coil that charges 200 laptops at the same time
Snowden and Manning are heroes.
Of course it can work. Crystal radio set can receive broadcasts without any source of power (other than the radio waves) from transmitters many kilometers ways. However, it is extremely inefficient - a 500kW transmission power may only result in a couple of mW to the headphones.
Same with wireless power transmission, except here we care a lot about the efficiency. The RFID chip probably nees miliwatts to operate (and the transmitter is 1W), so how about charging a laptop which needs 100W to operate - how much power will the transmitter have to use just so the user does not have to plug the power cord in?
It was also work that Tesla did developing the "Tesla coil" that directly lead to the development of the fly-back transformer, without which Filo Farnsworth wouldn't have been able to develop the TV set.
Why would the flyback transformer be crucial for a TV set?
Yes, all modern CRT TVs have flyback transformers to generate the EHT for the anode (and several other voltages), but this can be easily accomplished with regular 50/60Hz transformers. In fact, early sets actually used linear power supplies for EHT. Those power supplies had a drawback - safety. The CRT needs only a little current (a few mA) for it to work, but the power supplies could provide more than that (not at the nominal voltage, but still), which means that if someone touched the anode wire while the TV set was on, they were toast. The flyback transformer used in modern sets cannot provide enough current to kill a healthy adult, it also has the additional feature that since it is driven by the horizontal deflection circuitry, if the scanning stopped, the EHT voltage would shut down too and the CRT phosphor would not burn in one spot (computer monitors drive the flyback from a separate circuit, so they have separate protection to shut it down in case of a failure).
Yes, Tesla invented many useful technologies, but that does not mean that everything that he attempted to do worked or that it would have worked if he had enough money.
They drop off with the CUBE of distance.