Wireless Power

[qwerty123]

Hello,

 

I am sure you have all already heard about the efforts in making wireless power happen. One way I am looking at this is I think electro magnetic power. You know you get those toothbrushes that you put on the stand and they charge without any cables. Well I am wondering how they do this! Also I would like to know if you could do it on a larger scale with a larger voltage and current!? Any help would be appreciated greatly!

 

Thanks a lot

[5614]

Moving a magnet up and down a wire can induce a current, spose that's kinda wireless.

 

At the end of the day you can't really get much further than like 1cm.

 

I spose lightning is quite long distance wireless electricity though.

[reyam200]

can't they use radio waves? the old crystal radios didn't use any batteries. they got power from the signal its self.

[zking786]

Perhaps it uses energy from an electrostatic field that's setup in an area?

 

For example, if you have a Van De Graaf on and hold a tube light a distance from it, in a position such that that the tube is on a radius of the sphere of the Van De Graaf, you can light the tube up based on the potential difference between the ends of the tube. Perhaps it's something like that?

[swansont]

It's magnetic induction, as 5614 implied. A transformer where the primary and secondary are in two separate devices. The little knob/bump on one device is one loop, and the toroid that fits over it on the second device is the other. But there has to be overlap of the field to make it work.

[ed84c]

LASER's and the photoelectric effect?

[bascule]

Tesla had certainly been working on systems which utilized electrostatic induction:

 

http://en.wikipedia.org/wiki/Wireless_energy_transfer

 

The development of wireless energy transfer began in earnest with the lectures and patents of the electrical engineer Nikola Tesla (and is described in his 1916 deposition on the history of wireless and radio technology). In experiments around 1899, Tesla was able to light lamps filled with gas (similar to neon) from over 25 miles away without using wires. Tesla used a high frequency current (Prodigal Genius, O'Neill; pg 193). During his experiments in Colorado, he lit ordinary incandescent lamps at full candle-power by currents induced in a local loop consisting of a single wire forming a square of fifty feet each side, which includes the lamps, and which was at a distance of one hundred feet from the primary circuit energized by the oscillator (Century Magazine, June 1900).

 

The building of a global wireless energy distribution system called the Wardenclyffe Tower was started almost a century ago by Tesla but was abandoned because of lack of funds. The Wardenclyffe facility was meant to be the start of a national (and later global) system of towers broadcasting power to users as electromagnetic waves. There is some evidence that Wardenclyffe might have used extremely low frequency signals combined with a higher frequency signals. In practice, the transmitter electrically influences both the earth and the space above it. He made a point of describing the process as being essentially the same as passing electricity through a wire by conduction. Tesla believed that energy could be efficiently transmitted from the facility via longitudinal "non-Hertzian" (or maxwellian) waves (ed. see waves in plasmas for examples). Powered by an industrial alternator, the tower was apparently intended to inject large amounts of energy into a natural Earth circuit, using the Earth-Ionosphere network as the transmission circuit. Tesla called his wireless technique the "disturbed charge of ground and air method."

 

In various writings, Tesla explained that the Earth itself would behave as a resonant LC circuit that could be electrically excited at predescribed frequencies. However, Earth resonance would be of a very low frequency (about 7 Hz) which would utilize Schumann resonance. Alternatively, a surface or ground wave, similar to the Zenneck wave could have been utilized. Others believe that earth currents were to be utilized. According to Tesla, the planet's large cross-sectional area provides a low resistance path for the flow of earth currents. The greatest losses are apt to occur at the points where the transmitting and receiving stations are connected with the ground. This is why Tesla stated,

 

"You see the underground work is one of the most expensive parts of the tower. In this system that I have invented it is necessary for the machine to get a grip of the earth, otherwise it cannot shake the earth. It has to have a grip on the earth so that the whole of this globe can quiver, and to do that it is necessary to carry out a very expensive construction." ["Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power", p. 203]

 

To close the circuit, in theory, a second path would be established between the plants' elevated high-voltage terminals through rarified upper level atmospheric strata. The connection would be made by electrostatic induction or conduction through plasma. Tesla firmly believed that Wardenclyffe would permit wireless transmission and reception across large distances with negligible losses.