Interesting scientific exploration of Wireless Electricity by MIT, you could potentially recharge electric cars and maybe locomotives on the fly while they were moving:
https://www.ted.com/talks/eric_giler_demos_wireless_electricity
CMStPnP Interesting scientific exploration of Wireless Electricity by MIT, you could potentially recharge electric cars and maybe locomotives on the fly while they were moving: https://www.ted.com/talks/eric_giler_demos_wireless_electricity
Questions: Who governs the reception? How is it determined how much energy that a recipient receives (this should be known if this power is available to anyone who is able to receive it is to be paid for)? What is the effect on anything that uses a magnetic field in its work?
Incidentally, the propounder thinks that the FBI stopped Tesla; there was no FBI until in the niineteen thirties. I do know that Tesla's ideas were not well thought of at the time.
Johnny
This guy is so clueless that he has no idea how the Wardenclyffe installation was supposed to work (or what happened to it; hint: radio) and he thinks wireless Bluetooth-range power is somehow a conceptual breakthrough?
Useful, yes. Lots of applications, yes. Will it replace batteries for wearable devices? I don't think so. There is nothing magic in power RF, and the power doesn't disappear into the air because humans have the wrong impedance characteristics to couple to it directly.
About all the actual usefulness of this to railroading has long been described, for example in wireless coupling in transit KERS systems, spinning up bus or streetcar flywheels at stops as well as via regen.
I think people had the impression this would somehow magickally replace catenary for transcontinental HSR. Very little is further from truth.
(And yes, you could still power locomotives 'on the fly' from a Wardenclyffe-like setup with some better directional following in the elements of the array -- much of the control logic having been developed for cellular radio and now out of patent. But it's not cost-effective for the power density you need, and the other problems remain.)
I just did something that I, perhaps, should have done this morning: I read what Wiki has about Tesla.
Yes, his experiment on Long Island came to nothing because he was working on communication at the same time that Guglielmo (William) Marconi was, and when Marconi met success before he did, his backer, J.P. Morgan, refused to continue backing his efforts. It was not government that shut him down; it was economics.
As Overmod tells us, he was working on comunnication, not sending power through the air.
I also saw several websites that promise that, with their products that you build, you, too, can pull power out of the air, and cut your electric bill. This idea, of course, seems to promise that you do not have to depend upon using sunshine to reduce your bill.
Did they say that on Wikipedia? They could not be too much more wrong.
The Wardenclyffe system was explicitly broadcast power, and the structure of the tower head goes a long way toward showing how it would work. RF at power wattage would be routed to one of the direct antennae in response to a radio code 'request' from the receiver in line with it (billing for the power set up the same way' and a moving receiver like an aircraft would have sequential beams turned on in sequence to keep it powered. Morgan saw this as an adjunct, not a replacement, for wired AC, so it added to control over means of power electricity and not 'blocking a revolutionary new innovation'.
Principal issue was that power RF made wireless (radio as we understand it, too, but Marconi's system was only incidentally phone-modulated and basically impossible to divide into multiplex carriers) a dangerous if not impossible prospect. Also had the amusing ability to turn telephone lines and even fence wire into recipients of many horsepower on occasion.
The Marconi-Tesla business was much earlier, perhaps even before the Colorado experiments with 'telluric current' returns, and while Tesla ultimately prevailed in getting priority, the world had gone on to very different radio by then, following a far more sensible precedent set by Fessenden. But that is another story...
On looking at the Wikipedia article (https://en.wikipedia.org/wiki/Nikola_Tesla#Wardenclyffe) again, I see that he was at first interested only in power transmission, but when he asked for more backing so as transmit both messages and power J. Pierpont Morgan refused to support him.
At least Tesla showed the advantage of using alternating current instead of direct current for many applications.
Didn't Thomas Edison take him to court over the AC/DC thing and lost?
Principal issue was that power RF made wireless (radio as we understand it, too, but Marconi's system was only incidentally phone-modulated and basically impossible to divide into multiplex carriers, so inherently worse affected) a dangerous if not impossible prospect. Also had the amusing ability to turn telephone lines and even fence wire into recipients of many horsepower on occasion.
54light15 Didn't Thomas Edison take him to court over the AC/DC thing and lost?
CMStPnP Interesting scientific exploration of Wireless Electricity by MIT, you could potentially recharge electric cars and maybe locomotives on the fly while they were moving:
Short answer is NO.
The Witricity system is simply an application of coupled resonant circuits. Key issue is that the geometric mean of unloaded 'Q' of the resonant circuits needs to be substantially greater than the inverse of the coupling coefficient (see coupled resonator section of Radio Amateurs/ARRL Handbook published before the mid-90's). Max separation to get reasonable efficiencies is a few diameters of the power sending loop.
Witricity is working on EV chargers, but the charging "pad" is only a few inches from the corresponding pad on the EV.
- Erik
blue streak 1Telsa sort of proved that anyone within a mile of the emitter would get fried by the electro magnetic radiation. don't put us there!
How did he supposedly prove this?
We routinely tested if we were getting our 17KW ERP by holding up a fluorescent tube, which would promptly light up in the hand. Fun with mock lightsaber battles, too. You don't have a shock hazard from RF EM unless you can get current to flow in something, which requires effective coupling.
Tesla(note sp.) did in fact develop a RF 'death ray' based around 1.16MHz which induced what contemporaries noted was overstimulation of heart pacing. But that effect is easy to avoid by keeping away from critical frequencies.
The reported horror stories from billion-watt radar pulses (in the GHz range) usually have to do with selective water heating; think very large microwave oven. You will not get far with broadcast power in a water absorption window.
Having done an IEEE C95.1-2005 evaluation on a system operating in the low MHz range...
One frequency range of concern is the 50-100 MHz and as the human body is roughly a half wavelength, though it makes for a pretty lousy antenna. FM and TV broadcasts are typically horizontally polarized, so optimum coupling would require the human being horizontal. 17kW ERP suggests some antenna gain, broadcast implies a horizontally omnidirectional pattern, and the combination implies that actual power deposited in a person is going to be relatively low.
RF heating is an issue with MRI, though the low duty cycle limits the amount deposited.
FWIW, the resonant frequency for water is ~21 GHz (and very broad), though water starts becoming a lossy dielectric well below 1 GHz. This also shows up in the dielectric constant for water being about 80 at RF and below and much lower at optical frequencies.
The Witricity technology will fall into the limits set by IEEE C95.1-2005 for low power levels for transmission over several meters, the EV charging system has a much more limited range. Another issue is simply RF radiated power (i.e. far-field) for high power over several meters, versus the near field coupling used for power transfer.
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