electricity as a remote power source

[stebesplace]

Do you think it is possible to have electricity become a 'wave' and travel to a reciever? Take for example;

I want to power my video camera without batteries. I take a box like thing, and plug it into my camera where batteries normally go. I then have a control sending unit plugged into household current, which sends the electricity as a wave like a radio wave or something, to the box on the camera. Hence powering the camera from the household current minus the wire.

Problems:

Interfierence with other forms of wave communications. Phones, Internet, etc etc etc.
Feasability, ease of use
Cost Cost Cost
Production time

Is this something that other people have thought of? DO you think its scientifically possible?

This is just for fun,

-Steve

 

[f95toli]

Yes it is. A microwave owen is a perfect example. The microwaves transfer energy to the meal you are heating. If you put some metal in the owen it will generate sparks because the waves induce currents in the metal.

There have been suggestions to transfer electricity from solar cell-power plants in orbit around earth to the surface using giant microwave antennas. The problem is that if the beam is missaligned and misses the reciver antenna if could fry anyone that happened to be where the beam hit the surface (literally).


So yes it is possible BUT inefficient and dangerous.:Q

 

[dejitaru]

Yeah, I just bought a 24 pack of AA cells.

Crystal radios work the same way.

Unless you have a camera that uses very little power (hacked to less than a volt) and you can risk getting some sort of cancer, this may not be a practical solution.

I have used my microwave oven to power a few devices.

Interfierence with other forms of wave communications. Phones, Internet, etc etc etc.
That shouldn't be an issue (unless you're using UWB) as signal strength is the issue, not frequency or content.

Feasability, ease of use
That's where it fails as a home system.

Cost Cost Cost
Production time
That's no issue.

 

[K6]

here some microwave-powered plane.


Canadian
http://www.space.gc.ca/_images/csa_sectors/generic_space_tech/Image87.gif

http://friendsofcrc.ca/SHARP/sharp.html

http://www.space.gc.ca/csa_sectors/generic_space_tech/expl_prog/whatsnew/2000/nov2000.asp


japanese

http://www.kurasc.kyoto-u.ac.jp/plasma-group/sps/milax-e.html

 

[RossGr]

Can electricity be broadcast.~^ What can I say, turn on your radio.

It would be completly possible for the power companies to "broadcast" electricity, thus doing away with power lines and the the assiociated infrastructure, simply put up an antenna and turn on the lights. Why don't they do it?

2 major problems, and I am not sure which is the most important.

1) effiency, most of the broadcast power would be lost. You would have to broadcast at a constant power level without regard for useage, thus wasting a huge precentate of the generated power. Consider that the power exists in every point in space surrounding the broadcast antenna, the only powe being used is that at the recieving antenna, the rest is lost. So the total size of the recieving antennas as a ratio to the surface area of the broadcast sphere is the effeicency. This will be a pretty small number.

2) Billing, how would moniter the use of a customer and charge for the energy used.

As mentioned above power broadcasting will be done in tight beams from point to point, perhaps from orbit perhaps even from the moon. The technolog to do this exists now. It is a matter of economics.

 

[dejitaru]

Billing, how would moniter the use of a customer and charge for the energy used.

How do they get Nielsen ratings?

The energy could be sent burst to base stations and stored (perhaps killing blackouts).

effiency, most of the broadcast power would be lost. You would have to broadcast at a constant power level without regard for useage, thus wasting a huge precentate of the generated power. Consider that the power exists in every point in space surrounding the broadcast antenna, the only powe being used is that at the recieving antenna, the rest is lost. So the total size of the recieving antennas as a ratio to the surface area of the broadcast sphere is the effeicency. This will be a pretty small number.

The energy could be focused by electromagnets and waveguides (thus wasting more electricity). Also, the shape of the broadcast antenna would not permit a sphere of wasted energy.

A satellite could be positioned to collect cosmic rays which would then be sent to Earth (like in Sim City 2000 ).

Think of how much energy could be gathered from the sun by seebeck effect. This would be "free" energy, so an occasional misfire could be acceptable (that is, if it didn't kill people and start wildfires).

 

[RossGr]

I was pointing out the reasons why a simple broadcast of power will not be done. Not because it is impossible but because it is impractical. Now if you want to build a different system that is fine, but an intirely different subject.

How do they get Nielsen ratings?

Ok, so the power company will poll a statistical sampling of users and base their bills on that! Seems like a smart customer bring polled would LIE! "who me? Use electricity? NO, I take cold showers and read by candle light, When I surf, I have a bicylce, a generator and a teenager" Some how I do not think that the power company will be happy with people simply telling them how much power they use. And that is how Nielson POLLs work.
.

Also, the shape of the broadcast antenna would not permit a sphere of wasted energy.

Ok, so we brodcast into a segment of a sphere, now we have a .0001 % efficiency rather then a .0000001% So I only need to generate a 10 Megawatts to deliver a kilowatt, now were doing good! NOT

 

[stebesplace]

my brain is fried after reading all of this. i'm off to bed, i'll catch up with this in the morning.

-Steve

 

[everman]

I remember back in sim city 2000 you could build a microwave power plant which had a satellite which beamed solar energy collected in orbit down to the main facility. The only problem with that was when this high powered microwave beam went out of alignment, causing it to blow things up good idea for a directed energy weapon though.

 

[RickH]

It was done in 1899 by Nikola Tesla. He was a forgotten inventor that competed with Edison at the turn of the century. Edison wanted everyone to use DC current in their homes, Tesla discovered and promoted AC to overcome transmision line problems. Today we use AC, but who remembers Tesla. He also invented fluorescent lights, electric motors, and radio several years before Marconi. RRRR

 

[RossGr]

. He was a forgotten inventor that competed with Edison

Forgotten? By who? Tesla is well known and held in high regard, considering that he was a complete loon!

 

[dejitaru]

Tesla is well known and held in high regard, considering that he was a complete loon!

Well, who isn't these days?

Ok, so the power company will poll a statistical sampling of users and base their bills on that! Seems like a smart customer bring polled would LIE! "who me? Use electricity? NO, I take cold showers and read by candle light, When I surf, I have a bicylce, a generator and a teenager" Some how I do not think that the power company will be happy with people simply telling them how much power they use. And that is how Nielson POLLs work.

It certainly suits the advertiser's biling.
That was not meant as any sort of solution. (like the one two lines below it)

Ok, so we brodcast into a segment of a sphere, now we have a .0001 % efficiency rather then a .0000001% So I only need to generate a 10 Megawatts to deliver a kilowatt, now were doing good! NOT

Beh, you neglected everything else I said.
It could focus the energy as in microwave emmiters.

 

[RossGr]

And you are still missing the point of my post, what you are discribing is not a general broadcast, but a point to point system, totally different, not what I was talking about at all. The original poster was looking for a household broadcast system, I think that it would fail, not because of the metering but because a general broadcast is very inefficient. Consider that radio stations broadcast Megawatts of power and our radio antennas recieve milliwatts, this is a HUGE loss.

Consider that the larger the area of the recieveing antenna the more signal you can itercept, let us suppose a 1 sqaure foot antenna, and let us broadcast into a hemisphere, do some numbers, if you are 10 ft from the transimtter the power will be spread over and area of 200pi sq ft so your 1 sq foot antenna would be alble to gather roughly 1/600 of the broadcast power, so to get 1 watt to your device you would have to broadcast 600W. If you move further away the ratio gets worse. Of course you could have many of these devices running so there may be cases where this could be very useful.

Some other troubles, there will be other losses converting the recieved signal to usable power, The human body would work as a antenna, may recieve as much or more power then the device. You could potentialy electructe everyone in the room.

Sure you can develope a Point to point dish or waveguide sytem, it simply is NOT the very simple broadcast system I was talking about. And the original post was concernig a broadcast system

 

[stebesplace]

Ok, regarding a broadcast system, what are some stages in evolution of this technology, such that beit the technology and equipment we have now will not suffice, but in the near future, say 15 - 25 years, could there be any enhancements / improvements / etc?

I belive that when someone creates this, in the use to replace batteries, life will get much easier. Imagine not having to replace the battery in your remote every 6 months, or not needing to replace your alarm clock batter, albeit most plug into the wayy anyways. It would be alot easier to eliminate cords in the house, which could always potentially start fires. As well, to have your computer running virtually cordless. You could theoretically have your computer anywhere now, with no power cords to tie you down.

-Steve

 

[f95toli]

Originally posted by: stebesplaceOk, regarding a broadcast system, what are some stages in evolution of this technology, such that beit the technology and equipment we have now will not suffice, but in the near future, say 15 - 25 years, could there be any enhancements / improvements / etc?

No. Beacuse you still need to transfer enough energy to power your devices, nothing can change that. Any electromagnetic wave (light,microwaves etc) with a power density high enough to deliver that much energy would be very dangerous since the human body would absorb most of that energy if you got in the way (thats why a microwave owen can heat meat). And it would still be inefficent since you need to radiate the whole enviroment. Point-to-point might work but would still be dangerous.

/Tobias

 

[radioactiveballpoint]

Within your home, with a small range, using an EM field to power devices is very feasible to do and not exceedingly dangerous. It is however a little expensive since the parts (aka vacum tube) are not readily available in this advanced century we live in. Anyways, if you build a telsa coil with a vacum tube oscillator you can tune your circuit to only deliver max power at a certain range of frequencies and effectively cut out low frequency and very high freqency waves. If you can tune it to emit waves between about 500KHz and 1000KHz your waves will have low enough energy to where they won't cause problems like microwave radiation and the wavelength will be short enough to not burn you. If your range is relativley short, as in a couple meters, you can get plenty of power to your device without too much loss. At the device, you need to convert the EM wave to a phyiscal current in order for it to use any of the power. You can use an antenna to channel the waves through an inductor and that will convert the EM flux into a physical current. Then your camera is excepting DC power from batteries and you will be giving it an AC, so you can stick a diode in series with the inductor and a capacitor in parallel with that to convert your power to DC.
One quick thing about antennas... just making your antenna longer won't improve the performance. Waves interact with objects that are proportional in size to the wavelength. So the length of the antenna needs to be approximately the wavelength of the waves you want to capture, or an integer multiple of that, in order to deliver max power.

 

[f95toli]

Originally posted by: radioactiveballpoint
Within your home, with a small range, using an EM field to power devices is very feasible to do and not exceedingly dangerous. It is however a little expensive since the parts (aka vacum tube) are not readily available in this advanced century we live in. Anyways, if you build a telsa coil with a vacum tube oscillator you can tune your circuit to only deliver max power at a certain range of frequencies and effectively cut out low frequency and very high freqency waves. If you can tune it to emit waves between about 500KHz and 1000KHz your waves will have low enough energy to where they won't cause problems like microwave radiation and the wavelength will be short enough to not burn you. If your range is relativley short, as in a couple meters, you can get plenty of power to your device without too much loss. At the device, you need to convert the EM wave to a phyiscal current in order for it to use any of the power. You can use an antenna to channel the waves through an inductor and that will convert the EM flux into a physical current. Then your camera is excepting DC power from batteries and you will be giving it an AC, so you can stick a diode in series with the inductor and a capacitor in parallel with that to convert your power to DC.
One quick thing about antennas... just making your antenna longer won't improve the performance. Waves interact with objects that are proportional in size to the wavelength. So the length of the antenna needs to be approximately the wavelength of the waves you want to capture, or an integer multiple of that, in order to deliver max power.

It would still be too dangerous. 500-1000 KHz is basically the AM-band (radio). There are stories about people living close to the huge antennas that were used to broadcast AM-radio (I guess it is still used in some places). It turned out not to very healty. And remember that the power emitted by these antennas was just high enough to power "crystal radios", the current you could generate in the reciver circuit was very low (and the broadcast power was HUGE).
The principle you are describing is ok and I guess the Skin-depth of 1000 kHz in flesh is rather high so most of the radiation should pass through your body. But there are a few problems problems. First you need an antenna which is long enough: 1000 kHz is about 300 m so there is no way to use full-wave dipole antennas, you can of course use other types of antennas but they will always be big. The second thing is that the energy of
1000 kHz waves is much lower than for microwaves (>1 GHz) since the energy is w=h*f (Plancks constant x the frequency). The last problem is interference, turning on a device which emitts enough power to power for example a camera would probably fry all the electronics in the room (including your computer).

/Tobias

 

[DarkLance]

I still like the idea of a direct energy weapon. Similar to the so-called neutron bomb, a Microwave would no physical damage to structures. All the water would boil and the food would get over cooked, electrical equipment would be toast. But imagine using a microwave... oooo just sounds scary. Taliban? Fresh cooked in caves! I guess the only problem would be moving the satalite, oh and power this wave.

As for remote power? Why not just use a time-warp? lol, sorry joke... I remember reading something on electron wires. Someone somewhere was using basicly a wire made of electrons? (is this possible?) to send information. Get rid of your Cat-5, we got particles doing the work! OH! Idea! We have particle beams, right? Electron Microscopes? Could you not shoot electrons directly at the object? Its been awhile since I've thought about physics... But isn't electricity just the movement of electrons?

Hey, about Telsa, you ever play Red Alert? Did Eienstien get tanks and the like named after him.... noooooo... so whos the famous scientist now?

 

[Cogman]

Well, Regarding sending the Electrisity By Air, I have to wonder, Why not keep the same system we have in towns, and then erect a Huge Tower in the center of town to recive that towns energy (ok, For small towns like mine, For larger ones, 5 - 10) that way, our current system would read energy, But we could also go outside and see the pretty blue lights . The only problem with doing a system like this its it would make large Cities very vunerable to attacks, Think about it, couple of bombs here and BOOM!, The city of New York just lost its power.

 

[f95toli]

OH! Idea! We have particle beams, right? Electron Microscopes? Could you not shoot electrons directly at the object? Its been awhile since I've thought about physics... But isn't electricity just the movement of electrons?
[\q]

Yes,but electron-beams require high-vacuum (at least 10e-5 mBar) in order to go straight forward, otherwise the electrons will be scattered against the atoms in the air (like nitrogen and oxygen). A e-beam weapon would be very inefficient in an atmosphere.

/Tobias

 

[radioactiveballpoint]

A long time ago I read about some weapon they were developing which shot out two beams, one with a positive and one with a negative charge, and when the two made contact with skin it would connect the circuit and the current would flow through causing a slight burn. They said it'd be effective for crowd control and stuff, depending on the power of course, with a high enough voltage it would be deadly. I don't remember the details of course because it was quite a while ago but if anyone really wants to know i'm sure they could look it up...

 

[FuriousBroccoli]

If we're talking about Tesla, forget the air, he transmitted electricy through the ground plane, using a magnifying transmitter and a harmonic system. It didn't follow traditional EM theory though, and nobody's bothered to reconstruct his experiment properly since.

 

[MadRat]

If you weren't using something like charged ions for a direct line to the source you'd bleed off more energy then it was worth. Think about it, if you transmit an energy wave the potential decreases as you move further away from the source. Plus you only garner a small fraction of the energy in a direct line to the source, making most of the energy transmission a waste.

 

[PowerEngineer]

Originally posted by: stebesplace

Do you think it is possible to have electricity become a 'wave' and travel to a reciever?

Well, actually electricity is already an electromagnetic wave. As others have already pointed out, there's no problem creating electromagnetic waves; the problem is directing them to where you want them to go. This is especially true at very low frequencies, like the 50-60 Hz frequencies used for electrical power. And this is where the transmission lines come in -- they act as wave guides that direct the electromagnetic waves from one point to another.

 

[tranceport]

Anandtech Think Tank