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Old 9th Oct 2017, 3:45 pm   #1
Skywave
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Default Nikola Tesla

An historical snippet: today is October 9th, 2017.

161 years ago, at midnight, 9th. / 10th. October, 1856, Nikola Tesla was born.
And that event later produced a milestone in electrical engineering.

Al.
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Old 9th Oct 2017, 4:16 pm   #2
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Currently (pun intended) using one of his three phases. At least Elon Musk et.al. has brought his memory alive again in the Tesla cars etc., see http://www.businessinsider.com/who-i...or-2013-8?IR=T

Where has my rotating egg gone?
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Old 9th Oct 2017, 5:30 pm   #3
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Nikola Tesla 10 July 1856 – 7 January 1943 according to his biography.
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Old 9th Oct 2017, 9:03 pm   #4
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A complex and mysterious story- he was very much ahead of his time-like Einstein. Having thought up multi phase AC transmission while reading German poetry he built the Power Station at Niagra. Worked for Edison on his clumsy DC Generators then Westinghouse who won the AC/DC battle using Tesla know-how. Then Tesla develops a "wireless" power transmission system which would put anyone using cables out of business or that's what they assumed. It was probaly the equivalent of telling the Oil Industry that cars can run on water. Dies in poverty 1942 ? The Secret Service move in and remove all the documentation from his hovel-nobody knows who he was after that, even when they named things after him. The Tesla radio is a thing of beauty however. Some people think ithat this was all just a coincidence but he's central to everything down to the motor in a highly prized retro record player

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I always thought that they used much the same story line in the Bowie film "The Man Who Fell To Earth". They don't [actually] kill the alien there either. No need he's naive as well. Amazingly good film!

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Old 9th Oct 2017, 9:11 pm   #5
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I think I read somewhere that in his final years he lived in a hotel. Unable to pay, he left a “death ray” in trust of the hotel owner. This turned out to be a measurement bridge.
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Old 9th Oct 2017, 9:23 pm   #6
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That might just prove he was eccentric but you're right about the hotel-somewhere on "skid row" in N York, near the Park where he demonstrated Radio Control in the twenties. He didn't black out half the State with a measurement bridge though . There's a lot of info and unanswered questions still out there. Edison was probably a lot easier to manage and Westinghouse made a lot of money.

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Old 9th Oct 2017, 9:33 pm   #7
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If Nikola Tesla's wireless power tramsmission was anything but cold-pressed, extra virgin snake oil, then somebody should have independently rediscovered it in the meantime. You can't keep a good invention down. Newton and Leibnitz, Darwin and Russell, Swan and Edison .....
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Old 9th Oct 2017, 10:52 pm   #8
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It certainly worked and can be demonstrated working (look at wireless charging) but the claims were exaggerated considerably!

His namesake's company, Tesla (and SpaceX) tend to tell a big tale and actually deliver though which is interesting.
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Old 9th Oct 2017, 11:27 pm   #9
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Surely his idea of 'free electricity of all' and of wireless transmission of useful amounts of power were impossible? Even over short distances, a transmitted signal - even of considerable power - becomes so enfeebled it is useless for anything but comms? He may have been able to fry all local rabbits and light lamps, but only close by!
Wireless charging, which AFAIK works by simple magnetic induction, has a very short range.
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Old 9th Oct 2017, 11:44 pm   #10
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Quote:
Originally Posted by dave walsh View Post
Dies in poverty 1942 ?
Why the ambiguity over the dates?

Nikola Tesla 10 July 1856 7 January 1943 according to his biography.
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Old 10th Oct 2017, 12:29 am   #11
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Quote:
Originally Posted by Andrew2 View Post
Surely his idea of 'free electricity of all' and of wireless transmission of useful amounts of power were impossible? Even over short distances, a transmitted signal - even of considerable power - becomes so enfeebled it is useless for anything but comms? He may have been able to fry all local rabbits and light lamps, but only close by!
Wireless charging, which AFAIK works by simple magnetic induction, has a very short range.
Theoretically still possible but it wouldn't be very efficient, the antennas required at the distribution point and receiver would have to be pretty huge to transfer enough power or the wavelength very small. And then there's losses everywhere.

You can actually prove it's possible. Just hook one end of an LED to a 30-40 foot bit of wire and sling it up a tree, then ground the other half. It'll light up, just about. That's not a lot of power though. A modern version of the spark gap transmitter/receiver.

Really it doesn't work until you get to microwave and laser type frequencies and that's a whole different game.

Yes that's inductive. It is technically wireless power transfer though.
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Old 10th Oct 2017, 12:57 am   #12
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Wel I'd thought it was 42 but ok 43! The question is why did he die in those circumstances at all apart from being badly let down by Westinghouse? I don't have a fixed view on any of this Julie but a lot of people who ran cars on water or came up with Brown Gas etc got paid off! Many of those who used to routinely laugh at this kind of stuff have now gone quiet [including my wife]. This is because they are now seeing things on the news like AI, Gene Therapy and Bio-Tech techniques that were Science Fiction a decade ago [eg Minority Report]. Even the classic Multiple Universe notion seems to be standard in physics these days!

I almost took a machine minding job at Manchester Uni once. The Professor said "We are firing particles, I'm not sure what it is but I think it's going to be big"-it was basically a CRT type tube with magnets 12' across. That is now Cerne! A good example of suppression in the UK was the fate of the once lauded Professor of Electrical Engineering Eric [magnetic levitation] Laithwaite [also Manchester Uni] who dared to oppose anti-gravity convention-shamefull. Today's Guardian reports that Einstein was right about Gravity Waves and how Lister was derided for forty years because he wanted to use antiseptic procedures. The senior consultants would have had to consider that they might have killed a lot of people. If you want to see the forces Tesla encountered back then maybe take a look at tonight's [repeated] "Billion Dollar Deals and How They Changed Your World" BBC2 re money. It's all electricity

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Old 10th Oct 2017, 11:20 am   #13
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Quote:
Originally Posted by GeoffK View Post
Nikola Tesla: 10 July 1856 7 January 1943 according to his biography.
Which numerous other sources confirm. I can only conclude that the data I retrieved is in error. I was under the impression that that data was reliable.
My apologies to anyone who was mis-led, but my intentions were honest.
Thank you, GeoffK for the correction.

Al.
Oct. 10th.
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Old 10th Oct 2017, 11:38 am   #14
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Quote:
A good example of suppression in the UK was the fate of the once lauded Professor of Electrical Engineering Eric [magnetic levitation] Laithwaite [also Manchester Uni] who dared to oppose anti-gravity convention-shamefull.
Laithwaite was right on magnetic levitation but completely wrong on anti-gravity. Far from being suppressed, he enthusiastically shared his confusion about gyroscopes with any audience he could find. It was very embarrassing for his colleagues at Imperial College; they knew he was wrong but at first were reluctant to criticise him in public. Eventually one of the physicists decided that enough was enough and gave a public lecture showing the errors in Laithwaite's thinking; I was there. Unfortunately, to fully understand where he was wrong required the use of Langrangian (or Hamiltonian?) mechanics which was not taught to engineering students so Laithwaite might not have understood the rebuttal of his ideas.
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Old 10th Oct 2017, 2:56 pm   #15
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And that's the thing ..... If non-scientists don't really understand something, but it's sold to them as "sexy" by someone charming, then they can mistake the inevitable rebuttal for a cover-up by The Authorities.

The Laws of Thermodynamics tend to be pretty unforgiving. As tempting as it is to want to believe that powerful interests are trying to suppress a cheap and abundant energy source, it's much more probable that there is just no such thing as a free Joule. Someone who discovered it independently would just Open Source it, and it would be all over the Internet and being independently verified before the Men In Black™ could do anything about it.
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Old 10th Oct 2017, 3:34 pm   #16
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Stefan Marinov from Bulgaria was a believer in free energy... he had a chat with (I think) Frank Ogden, editor of Wireless World, about electric ball-bearing motors and Frank published it. Stefan claimed that the output energy was in addition to the heat dissipated due to I-squared R losses. I made one and it worked! Sadly, my instruments were not accurate enough to show that 240W electrical power in, resulted in 240W of heat AND 5W or so mechanical power...

Regrettably, Stefan Marinov killed himself. I tend to think Tesla went a bit doolally in the end, as nobody has managed to prove him right yet (and there must have been many attempts!
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Old 10th Oct 2017, 4:17 pm   #17
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I've never come across an eye-witness report before Dave-fascinating.
What you say is clearly accurate [although the Langran-Hamilton mechanics aspect is new to/beyond me] but I suppose it was the overall attitude that shocked me at the time. His colleagues seemed deeply uncomfortable with their own actions, even if he was wrong. The Professor was clearly an open target like Tesla and suffered for it.

Similarly, Laithewaite never even seemed to get proper recognition for the magnetic levitation system that he developed which was both a ground breaking re-configuration of the AC motor and not isubject to any technical dispute.
Professional jealousy? or possibly because the Japanese built a High Speed Railway System while we were still trying to get from Manchester to London in two hours.

Ironically there is now a new resurgence in anti-gravity propulsion research at present in both the "alternative" and traditional disciplines. Or is that just what we knew already finally coming to light. It's no secret that the stealth fighter had long been in service before it was officially rolled out in the eighties. Maybe I'm biased but the Royal Society Xmas Lectures given by Eric in the sixties have always stuck in my memory as a piece of metal levitated across the lecture room. Proper stuff, no patronising delivery and likely to give future Health and Safety Officers a heart attack

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Old 10th Oct 2017, 4:53 pm   #18
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There are eyewitness accounts of Tesla's having demonstrated wireless discharge lamps, but of course that's a far cry from long distance heavy current distribution.
I've attempted to read some of his papers, but found them heavy going, not due to complexity, but simply because of the difference in theory and perspective from current understanding - which is not to say that they are incorrect.
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Old 10th Oct 2017, 9:05 pm   #19
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Lighting a discharge tube wirelessly is fairly easy. Remember in an electric field of so many volts per metre, what that means is that is the voltage that will appear between two points a metre apart and perpendicular to the direction of travel of the wave. And close up to the antenna, most of the energy will be in the electric field; it takes about five or six wavelengths for the energy to reach equilibrium between electric and the magnetic fields. If the voltage is enough to strike up a discharge, then the tube will glow; the current will be limited by the power density in W/m2. It's just like the trick where kids dare one another to stand under a pylon holding a fluorescent tube vertically upright, or the less-spectacular version involving bending the leads of a high-brightness LED apart and holding it near a mobile phone while it is talking to the cell tower.

The problem is, it doesn't actually transmit very much power to the load, and the old inverse-square law prevents it from scaling well. It's a very impressive conjuring trick, but that's really all it is; it can't be turned into anything practical. And that is not a limitation of present technology, that can be overcome by inventing the right thing; rather, it is a fundamental limitation of the universe. If you were feeling suitably masochistic, you could do the maths for yourself and see why it won't work. You have to get at least 50 watts into a house just for a modest level of illumination in a couple of rooms, never mind appliances. If it gets hot for a living and is any bigger than a soldering iron, forget about it.

The idea of plentiful cheap or free energy is undeniably an alluring one, and there is no shortage of easily-impressed people who don't understand intermediate-level thermodynamics as well as they think they do -- nor con-artists looking for investments in perpetual motion machines they are building (curiously, none of them appear to be able to afford an alternator to couple to their inventions .....).
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Old 11th Oct 2017, 12:34 am   #20
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That's a very good summation of "snake oil" Julie and [if I can say so] free from bias. I haven't got any of the advanced knowledge of energy fields etc that others have [in fact last night's University Challenge Questions on electrical units had me baffled]. In terms of transferring useful amounts of power wirelessly though I'd always thought that Tesla's aim was to utilise the planet's natural resonant frequency which has much higher current prospects and even in my ignorance, seems to make sense. Anyone can light up a flourescent tube! Soldiers in step over a bridge can destroy it and this factor is a also basic aspect of AC electrical distribution [I think]. If you get down to 8 or 9 cycles the human body is at risk of being micro-waved to death! I won't wander further into into music or Joshua and the Walls of Jericho

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