electricity as a remote power source

[stebesplace]

Lets step back from the situation for a moment.

Lets say i am in a controlled enviroment. Now without referencing or using 'microwave' devices, I want to power my remote control, in the house, i turn on my 'generator' like box which is plugged into the wall socket, and it sends out frequencies, containing the required electrical field, such as a low power emf field, which would be able power to send a sweeping field out in the room, and the remote picks up that frequency and uses the power being supplied from the wall. I can not picture this on any larger scale other than this example.

The frequency would be an issue i think, as it would disrupt our senses, possibly providing a shock, like lightning. So a way to overcome that would be? Hopefully to not wear all rubber materials!!

-Steve

 

[MadRat]

Okay, if you insist a recap:

1) electromagnetic waves are a poor electrical conduit
2) electrical wire makes a good electrical conduit
3) superconductors make a great electrical conduit

It would make more sense to use energy that is reflective (i.e. light waves) and the environment would need to be a perfect reflector so that no energy escaped the microcosm nor bled into the surroundings, the mirrored surface of the parameter. So, if you want to use wave energy then use light and a perfect reflector around the entire parameter so that the transmitted energy has no place to go but the destination. Its easier to use electrical wire...

 

[Keego]

All I remember from Physics class was that if you had 2 inductors set to the same frequency, and ran current through one of them, the other inductor would pick up on that current. I think the first tests involved a distance of 10 ft.

 

[Sukhoi]

Originally posted by: Keego
All I remember from Physics class was that if you had 2 inductors set to the same frequency, and ran current through one of them, the other inductor would pick up on that current. I think the first tests involved a distance of 10 ft.

Isn't that something with the electromagnetic field though?

I have to take Physics E&M next sem...getting scared already. 🙂

 

[Keego]

Yes it is the E-field. I'm an EE I should know this stuff but I don't 🙂

 

[Confide]

Ok, well heres my $0.02 on this whole deal, assume everyone on earth that wants Microwave power, is connected to some sort of Broadband (HYPOTHETICALLY). A totally integrated house, which when you fick on a light sends a signal from the home, to the Power company via the broadband connection be it T1; DSL; cable etc, which says basically "Hey i need this much energy to run my lights do my laundry and play warcraft III" 🙂. So when ever you turn on an item which requires energy, the signal is sent and the power companies Super Uber computer ups the amount broadcasted over airways, when the lights go out a new signal is sent via broadband telling the system to stop sending that energy. Theoretically the system would only respond to connections which it has accounts to bill for, thus only subscribers to the wireless engery would be able to use and be billed for it. I know pritty out there idea, but is it really that crazy? i suppose you still have to factor in the possiblity of cancer. I dunno blow holes in this theory, after all....
Just trying to think outside the BOX =]
Lemme know what you think.
Confide.
P.S. The power company would probably a run Windows and people would find some DNS attack to crash the server hahah

 

[PowerEngineer]

Originally posted by: 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.

This probably isn't the best etiquette to quote myself, but you really should consider the implications of what I've already said. 🙂

Electromagnetic waves are inextricably linked to electricity; electric current (both AC and DC) occurs with electric and magnetic fields; if you talk about electrical current, then you're talking about electromagnetic waves too. As RossGr pointed out, the "broadcast" of electromagnetic waves from a point source means that the density of the available power will decrease as the cube of the distance, meaning that the antennas needed to collect the power would have to be huge (like 10 feet in diameter to power a light bulb from a distance of 40 miles) and also that you wouldn't want to walk too close to the transmitter!. That's where the transmission lines come in! They provide wave guides that focus the power carrying electromagnetic radiation along predetermined linear paths from the generating plants to the loads. The wiring in your home supports the current flow that guides the electromagnetic waves into the motors, power supplies, light bulds, etc. Thanks to these wire wave guides, the density of the power available through the electromagnetic radiation does not drop with distance. (Note that reductions in voltage accomplished through transformers before the current gets to your homes do reduce the power densities.)

Because of its frequency, microwave radiation is much more easily directed than the low frequencies used by electrical power. A properly designed microwave transmitter can emit its full power in one direction without much diffusion. For 50-60 Hz, you need a wave guide to fix direction.

If you run an alternating current through one coil, it will cause an alternating magnetic field. Another coil in proximity to the first will have current induced to flow in it as a result of the changing magnetic field from the first coil that passes through its coils. This is the basic theory behind the transformer. Transformers use coils wrapped around iron cores; the iron cores funnel the magnetic field from one coil to the other with minimal leakage (and therefore greater efficiency).

 

[Akira13]

I'm still hoping that one day I will invent a device that harnesses the huge amount of background radiation in the universe, and converts it to useful power. Then we could just minituraize the devices and use them to power whatever we want, wherever we want (assuming you're not inside a shielded area. My electrical engineer colleagues tell me that it's more of a materials sciences thing, but hey, I can dream, right?

 

[sao123]

Lets look at this from a physic(s)al perspective:

Electricity is a flow, or movement of electrons. Electrons have mass. The only way, you are going to move electrons from a remote source to, say a mobile device, is in a plasmatic form... AKA...lightning...static electricity... @ high voltages. Nothing short of high voltage, or a particle accellerator will propell the electron fast enough to free it from the atom and push it to a remote loaction. Remember, electricity takes the least resistant path to the ground, so this is semi-unfeasible. Because you will be unable to guide the electron to your intended destination, once it has left its origin.

The reason your logic is going wrong is the following...your comparing apples to oranges...
Radio waves, etc...do not transmit energy...they use energy to transmit a pattern, which can be translated into data. Obviuosly the frequency of the wave pulse does not change, that what allows the transmitter and reciever to sync. How the data is read is the wave amplitude. Since we cannot readily convert mass to energy... (IE) send the electron as a wave, then turn the wave back into mass (the electron)... there has to be an alternative....

However it is not a wave or beam.... it is a vector field.
The best way to accomplish such a thing would be to figure out a way to not transport the electrons, but to figure out how to move the ones currently already inside the remote device. The could be done by surrounding the device with an electomagnetic field. Which are easily created. Fields are 3d & spacial, having magnitude at all points. A wave travels in a straight line, and would not be recieved properly. This field would exert force on the entire circuitry of the device, thus pushing the electrons into flowing.
This theory is based on the workings of an electric generator.

However the drawbacks to this design are...

1)Fields dissipate rapidly when operated over large distances.
2)The amount of energy spent to maintain the field grows exponentially, compared with the amount of electron movement created @ the device. Remember, most of the field is wasted, only volume of the device circuitry is effectively used, compared to the size of the overall field.
3)Fields of this size and magnitude, would cause cancer and other cellular disorders in living tissue.

Once again, this is highly unfeasable also.

 

[RossGr]

Sao123,
If electric Fields do not transport energy, how does a radio work?

The fact is EM fields DO carry energy, you need to review your basic EM theory.

BTW: you seem to descriping AM raido transmission, in modern FM radio, the signal is carried in changes in frequency.

The fact is, in either type of transmission, ENERGY carried in the EM wave induces electron motion (current) in the antenna of the reciever, this small current is amplified and demodulated to reproduce the original audio signal. This all demands that the EM wave contains energy.

 

[sao123]

Actually, I was referring to neither AM or FM, but digital signal.
EM waves/field are...exist as energy.. not contain/carry/transmit energy.

anyways...The properties of these waves are merely measured upon reception, whether it be frequence, amplitude, or length. They cannot be captured and converted into mass (IE... electrons).

As I stated,

However it is not a wave or beam.... it is a vector field.
The best way to accomplish such a thing would be to figure out a way to not transport the electrons, but to figure out how to move the ones currently already inside the remote device. The could be done by surrounding the device with an electomagnetic field. Which are easily created. Fields are 3d & spacial, having magnitude at all points. A wave travels in a straight line, and would not be recieved properly. This field would exert force on the entire circuitry of the device, thus pushing the electrons into flowing.
This theory is based on the workings of an electric generator.

the EM field can be used to to create a current in the circuit.

Quoting your own text...
The EM wave induces electron motion (current) in the antenna of the reciever

"wave" should be "field" in this case though

This is exactly the principal I am describing... just to a larger scale... used to power an entire circuit...
Obviuosly though it is going to take a larger, stronger field.

 

[RossGr]

EM waves/field are...exist as energy.. not contain/carry/transmit energy.

This is simply incorrect, they can and do carry/transmit energy. How do you suppose the energy from the sun reachs the earth? It is transported in the form of EM energy we call light.

 

[sao123]

This is simply incorrect, they can and do carry/transmit energy. How do you suppose the energy from the sun reachs the earth? It is transported in the form a form of EM energy we call light.

Duh...

How does energy move? Waves.
A wave is not a transmission media for moving energy.
Waves are any defined as the state of energy in motion...waves themselves do not actually exist without energy in motion.
Waves dont carry or transmit energy, waves are the movement of energy itself.
All non-potential energy (which is the only form of non moving energy.) exists as waves, because it is in motion.

If what your are saying is true...
Thats like saying walking moves your body. Walking doesnt move your body... you yourself walk.
Waves dont transmit energy, the energy itself moves as a wave.

 

[RossGr]

Have you ever heard of the Poynting vector?

P= (ExB)/mu

E is the E field vector , B is the Magnetic field vector , mu is mu sub zero, the permeability of free space,

P is a vector pointing in the direction of travel of the propogating wave representing the direction of the energy carried by the field.

Have you ever really studied Electomagnetic theory?

Are you familiar with Maxwells equations? Click on the "god said" link in my sig.

If you are not familiar with the symbology used in those equations, then you have not studied EM theory.

 

[Woodchuck2000]

Well, actually electricity is already an electromagnetic wave.

While on the subject of things which are simply incorrect...

What everyone is talking about seems to be transmission of energy using microwaves. You convert electricity into microwaves then use a chunky inductive array to turn them back into electricity at the other end. Its the same as putting batteries in your torch then shining it on a solar cell. You're transmitting energy, not electricity. EM waves could be used to produce a heating effect with the same energy.

As far as transmitting electricity goes, the only way I've seen it done is to use a laser to ionise a column of air. The air then temporarily becomes conductive and a current can pass down it (similar to flashes of lightning, and indeed the good old Tesla coils in red alert...)

Without some kind of medium to allow electron flow however (be it wires or ionised air) you can't get 'electricity' from A to B.

 

[Agent004]

Originally posted by: sao123

This is simply incorrect, they can and do carry/transmit energy. How do you suppose the energy from the sun reachs the earth? It is transported in the form a form of EM energy we call light.

Duh...

How does energy move? Waves.
A wave is not a transmission media for moving energy.
Waves are any defined as the state of energy in motion...waves themselves do not actually exist without energy in motion.
Waves dont carry or transmit energy, waves are the movement of energy itself.
All non-potential energy (which is the only form of non moving energy.) exists as waves, because it is in motion.

If what your are saying is true...
Thats like saying walking moves your body. Walking doesnt move your body... you yourself walk.
Waves dont transmit energy, the energy itself moves as a wave.

hhhm, let's start with a low/basic level definition of energy. Energy is defined as the ability to do work.

If Waves are any defined as the state of energy in motion, then work must be done in generating the motion and wave is such motion, therefore wave must contain/carry(and hence transmit) energy => wave is a media for transmitting energy

However, if a wave is not a transmission media for moving energy(ie, it doesn't carry or transmit energy) and defined as defined as the state of energy in motion. Hence the motion doesn't contain energy. But no energy = no work done (or can't do work) = no motion ( a contradiction) Hence the motion must contain/carry(transmit) energy

Summary: Energy can move if and only if there exists a transmission media and wave is one such media. Then necessarily, wave must contain/carry/transmit energy

 

[sao123]

hhhm, let's start with a low/basic level definition of energy. Energy is defined as the ability to do work.

If Waves are any defined as the state of energy in motion, then work must be done in generating the motion and wave is such motion, therefore wave must contain/carry(and hence transmit) energy => wave is a media for transmitting energy

However, if a wave is not a transmission media for moving energy(ie, it doesn't carry or transmit energy) and defined as defined as the state of energy in motion. Hence the motion doesn't contain energy. But no energy = no work done (or can't do work) = no motion ( a contradiction) Hence the motion must contain/carry(transmit) energy

Summary: Energy can move if and only if there exists a transmission media and wave is one such media. Then necessarily, wave must contain/carry/transmit energy

Partially right. Energy is defined as the ability to do work or the ability to cause heat to flow.
Work is defined as: the movement of mass a net displacement.
Since energy has no mass (massless photon), no work can be done on it. (It can do work on mass though.)
By very definition motion is kinetic energy, motion does not carry/transmit/contain energy, motion is energy in kinetic form.
Energy(motion) is not carried by a wave, but the wave describes the properties of motion itself.
Frequency, Wavelength, Apmlitude.

Motion does not guarantee work has been done.
Heat is energy... heat does not do work. Heat is a measurement of the motion/velocity of atoms, however the atoms vibrate in a periodic motion, which results in a net displacement of zero. Therefore no work is done.

yoohoo hello? Has anyone ever heard of the "particle/wave duality theory"? It describes that waves are the substance of motion. All motion exists in wave form, including both energy and mass. Nothing can move without being in wave form.

Result... anything in motion is defined as in a wave state with measureable wave properties.
Waves are a state...not a medium.

 

[RossGr]

Do you not see that an electro magnetic wave induceing motion of electrons in an antenna as work being done by the EM wave? Where does the current in an antenna come from? How can we get current flow if there is no energy being transproted by the EM field broadcast by a radio station? When the say a radio station has a 5M watts transmitter, what happens to the 5M watts It puts into creating a radio signal.

Sau, you did not respond to my questions about Maxwells equations. Are you familiar with the math mathematics of EM fields?.

Also,those of you who do not believe that an EM field (or photon, they are the same after all!) can do work must explain the energy we recieve from the sun.

 

[Agent004]

okey, sao, if I take your definition., then I see this:

Energy is defined as the ability to do work or the ability to cause heat to flow('cause heat to flow' is work, otherwise how on earth do you get it to move/flow? Let's leave that for now) and Heat is energy, then energy can be also thought as the ability to cause heat energy to flow(since heat is energy, just a particular form of energy) by your definition. Then it necessarily means you can actually do work on energy(or a particular form of energy). How can this be true when you also states 'no work can be done on it(heat)'?

Also, consider EM waves are self-propagating(do correct me if I am wrong) it does work on itself?(I do know the interaction of electric field and magnetic field causes this) If the wave doesn't have energy, how can it self-propagate at all?

'Work is defined as: the movement of mass a net displacement.' This is a funny thing. Let's consider the scenario at a soccer/football match. The referee runs through out the match, but have little net-displacement to show it. So suppose the referee starts at the middle of the pitch and ends at the middle of the pitch, he ran for the whole game and accord to your definition, he didn't do any work at all?! 😛 That's obviously not the case, of course 😉

'motion does not carry/transmit/contain energy, motion is energy in kinetic form.' If motion is energy but in kinetic form and you are telling me motion does not carry/transmit/contain energy, then what is it?

Since 'motion is energy but in kinetic form' => motion is energy => motion contains energy <=> wave contains energy(since such motion is wave or called wave for that matter).

Otherwise it's like saying water is water, but water doesn't contain water? Or Mass is a form of energy but mass doesn't contain energy? What exactly are you trying to say?

 

[Woodchuck2000]

Firstly, my apologies for picking bits out of your post...

Work is defined as: the movement of mass a net displacement.

By who? For a start, the definition is not homogenous. Aside from that, it doesnt make sense...

Since energy has no mass

Energy is a property. You can't hold 2j in your hand.

By very definition motion is kinetic energy, motion does not carry/transmit/contain energy, motion is energy in kinetic form.

Motion is the variation in displacement of a body, relative to another body, with respect to time (i.e. dx/dt relative to an arbitrary origin.)

heat is energy... heat does not do work. Heat is a measurement of the motion/velocity of atoms, however the atoms vibrate in a periodic motion, which results in a net displacement of zero. Therefore no work is done.

Heat (ie. absolute temperature) is a property of matter. It has absolutely nothing to do with the velocity of atoms. A ball bearing will not change 'heat' if it accelerates. The heat will not change if the net displacement of the atoms is greater than zero (ie. it's moving.)
Heat does not do work because no energy is transferred. The motion of the component atoms is irrelevant to the statement.

Waves are a state...not a medium.

A wave can be used to transfer information. It is therefore a medium by definition.