Naked Science Forum
Non Life Sciences => Technology => Topic started by: Karsten on 30/05/2009 18:35:43
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The Tesla turbine seems simple. It is reversible and can be used to pump. It works for air or water. All I like, but how efficient is it in comparison to other turbines/pumps? Flat disks seem to be less efficient to be moved by/move air or water.
What do you think? What is the great benefit if there is one?
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I don not think that it works as good. The main reason is because there is less surface for energy transfer.
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Tesla must have had a fantastic publicist. His name continues to come up in lots of examples and the myth of the superiority of his ground shattering inventions lives on. He did some good stuff, no doubt, but his name seems to be revered out of all proportion. I wonder why. Even David Bowie played him in the Prestige (a brill film, btw).
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According to this
http://en.wikipedia.org/wiki/Tesla_turbine
It's not brilliant.
"The turbine efficiency of the gas Tesla turbine is estimated to be above 60, reaching a maximum of 95 percent. Keep in mind that turbine efficiency is different from the cycle efficiency of the engine using the turbine. Axial turbines which operate today in steam plants or jet engines have efficiencies of about 80 - 98 %. "
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I just wonder why so many people are all over it. Of course, Tesla is a name that attracts certain people, I just want to know what is the big deal and why now.
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Because we are more advance in technologies now, and it may be that the discovery of new gases can develop a better turbine.
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What new gases? How do they help a turbine perform better?
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Tesla must have had a fantastic publicist. His name continues to come up in lots of examples and the myth of the superiority of his ground shattering inventions lives on. He did some good stuff, no doubt, but his name seems to be revered out of all proportion. I wonder why.
Well, he did more or less invent electrical engineering as we know it; AC power transmission, transformers, induction motors, fluorescent bulbs, heterodyne radio receivers, to say nothing of wacky stuff like Tesla coils. There's even evidence that he knew about X-rays before anyone else (although he didn't know what it was).
Basically, if you look around you right now, all of the plugged-in and wireless stuff are largely technologies that are directly traceable to his patents.
In some cases others did improve his stuff and make it work (like the induction motor), but nevertheless he's nothing less than the greatest electrical engineer that ever lived; and that's probably not hyperbole.
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There is more to Engineering than having bright ideas. He definitely 'got there first' with a lot of his ideas but did many of his actual designs get into long term use? In the sense that he had a lot of great ideas which were taken up and developed more successfully elsewhere, perhaps he should have been British?
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""Well, he did more or less invent electrical engineering as we know it; AC power transmission,""
NO HE DIDN'T. British John Hopkinson had devised 3 phase AC before Tesla had even arrived in the USA.
I find the claims that Tesla invented X Y an Z farsical like a radio controlled boat in 1896 when the components needed to do it didn't exist.
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He would have been a great "ideas Man" to have in a development lab. He would have spent weeks swanning around and then he would come up with an idea which the 'workers' could have taken, refined and produced something worth having.
I just don't know where he got his fantastic reputation from. I bet if his name had been Bert Spriggs no one would have remembered him.
I believe the Russians invented most things, in any case.
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What new gases? How do they help a turbine perform better?
I do not -know-, afaik our ingenuous can be use to upgrade stuff.
I would say that 99% of what you are saying is completely right, but there is still that 1% remaining.
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""Well, he did more or less invent electrical engineering as we know it; AC power transmission,""
NO HE DIDN'T. British John Hopkinson had devised 3 phase AC before Tesla had even arrived in the USA.
Well... true but Tesla invented/patented the induction motor; AC power wasn't much use without an AC motor, and that was the first practical one (well fairly practical anyway).
I find the claims that Tesla invented X Y an Z farsical like a radio controlled boat in 1896 when the components needed to do it didn't exist.
He demoed it to *loads* of people though.
So far as I can tell it wasn't radio controlled in the sense you mean though, it was near-field induction. I think it's usually described as 'remote control'.
I mean he's got this image as some kind of mad scientist/genius that invented everything, that's not true, but the converse isn't true either, he really did invent some key technologies; and he was really strong on resonance; that's the fundamental thing that makes radio work.
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The induction motor is not the only reason for using AC. It is more efficient to generate than DC and it enables the use of transformers.
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Somebody posted some of Tesla patents and they don't make much sense. He seemed to have very muddled and mysterious ideas which these days with our must greater knowledge we would just laugh at.
It was claimed that the boat could steer and had proportional speed control which I find inpossible to believe in 1896. It would have been difficult to do 10 or even 20 years later.
There seems to be very little hard evidence that Tesla did very much of any practical value.
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He did do it, he demoed it at a fair, but in 1898, not 1896. Tesla had already applied for his patent on radio (using sine wave carriers) a year before. Eventually the courts would rule (after his death) that he had invented tuned radio receivers/transmitters before everyone else. So he pretty much invented the concept of radio as we know it today, except for untuned spark gap transmitters which are no longer used.
Incidentally, the patent office didn't believe a word of any of it either; but then he demoed them the boat!
http://www.pbs.org/tesla/ins/lab_remotec.html
There's a picture of the inside of his boat:
http://www.pbs.org/tesla/ins/remsubpop02.html
IMO the reason he was able to do it before everyone else was probably to do with Tesla coils- he invented them in 1891. They're tuned circuits, and if for example you set up one Tesla coil up next to another, and start it sparking the second one will start to spark, even if it's switched off, but only if it's tuned to the same frequency!!!
So he was just riffing on a theme really; resonance is the key invention in modern radio and Tesla coils, and if you've got resonance and plenty of power, and a bit of lateral thinking radio control is not that difficult.
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NO.
I can just about believe it was possible to send a start and stop signal for a boat in 1898 but proportional control of speed and steering.. NO WAY.
That would have to wait for a couple of decades at least.
NO HARD EVIDENCE.. Just like so many things to do with Tesla. Just like with all his claims for radio.. You can see Marconi's early apparatus. You can see the remains of his radio stations. There is one near me.
I can't believe serious engineers and historians of science give much credance to Tesla.
Marconi holds the patent for tuning.. The famous patent 7777
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Proof by (dis)belief is a well known fallacious form of reasoning.
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Some of Tesla's claims (or those of his psuedoscientific followers) are plain stupid...like lighting up 20 lamps 10 miles away without wires, powering, not just controlling. So you tend to think he is all froth and myth and no substance at all. Then there are the loonies who think various authorities have destroyed his aparatus and documents.. As someone said (I think Sophie) why on Earth hasn't somebody demonstrated these things in the more that 100 years since Tesla did them??
Marconi doesn't escape criticism. Many beleive that the 'first' Atlantic crossing by radio in 1901 didn't actually take place. The frequency, time of day and equipment available at the time don't add up.
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Well, the boat does seem to have happened. The patent is actually a real patent (http://www.google.com/patents?id=T1VrAAAAEBAJ&printsec=abstract&zoom=4&source=gbs_summary_r&cad=0_0#PPA1,M1) and it happened at a fair, lots of people saw it. The patent seems reasonably well written and there's been people who built reconstructions.
The wireless power thing may or may not have happened. But it is possible to do that, if you throw enough power in at the transmitter end, and you have a big transmitter.
Certainly he had a lot of wacky ideas though, he thought a lot of his waves went through the ground, when it must have been going through the air, but then again, ground planes and their interaction with radio waves were not at all well understood back then, so I'm prepared to cut him some slack on that. Still, whenever it has been rebuilt his hardware does seem to work as advertised, even if some of his theory behind it is now known to be wrong.
He also was well known to be a bit nuts, in modern terms he seems to have had pretty serious synesthesia and perhaps a touch of OCD.
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We will have to agree to disagree.
Have to remember in 1898 all they had was spark gaps and coherers. How could you have proportional control??
Unless you or someone can explain in detail how it could be done when the components and techniques needed didn't exist I will continue to think it is all sham.
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We will have to agree to disagree.
Have to remember in 1898 all they had was spark gaps and coherers. How could you have proportional control??
He had more than that, because he also had tuned circuits and electric motors. He could easily use the radio signal to change the angle of a rudder for example based on how long the signal was transmitted for.
And he did seem to also have multiple channels.
Unless you or someone can explain in detail how it could be done when the components and techniques needed didn't exist I will continue to think it is all sham.
Well, he didn't necessarily need proportional control to drive a boat around, so I don't see how you can even make that leap. There's multiple documents that all seem to point to him having done a remote control boat, including the patent, which includes a circuit diagram and a description of the coherer and how it was employed and built.
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Is there any point in this discussion?
Tesla had a lot of good ideas and he made a start at getting some of them to work. Does that really make him as 'great' as his fans think? I don't think so. He might have better if he'd been born fifty or a hundred years later because technology would have allowed the realisation of his designs.
He was a real person but a lot of his claimed activities were on the mythical side and shrouded by history.
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He's certainly not as good as some his more excessively open-minded fans think- he never built a death ray and never created a device to make the whole world oscillate and bring down tall buildings. That's almost certainly untrue.
But all the more mundane stuff, like remote controlled boats, Tesla coils, induction motors, some sorts of radio- stuff we take for granted today, these are well documented and he really did have a major hand in along with others like Edison, Marconi etc. etc.
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I think the proof of the pudding is in the eating.
There just aren't many devices around which are directly traceable to Tesla without someone doing extensive re-engineering to get it working properly. His 'wireless' work was really bad-neighbourly. He would have been the only person for miles around who could operate a link of any sort. Spark transmitters have not been allowed for decades - for good reason.
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Tesla did a variety of different things, many of them were spark-gap, but even then usually filtered through a very high-q filter, so no, not really; if you filter a spark gap enough you no longer have a spark gap transmitter, as it only radiates in the pass band- the really evil thing about true spark gap transmitters is that they radiate indiscriminately.
At least one of Tesla's experiments involved a steel wire oscillating at a lofty 50khz(!) in a magnetic field, and using that as his oscillator. Given the lack of valves, he went much further than anyone in producing practical systems.
I think if you read the wikipedia page:
http://en.wikipedia.org/wiki/Invention_of_radio#Tesla
Tesla comes out pretty well in comparison with everyone else. Even Marconi, who is often credited with inventing radio got most of his stuff from Tesla, and his famous experiment is now rather in doubt. And in America at least, his patent was finally overturned in favour of Tesla.
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The Tesla turbine seems simple...
..What do you think? What is the great benefit if there is one?
Well there is this (NSFW)!!!!:
http://ladycartoonist.com/archives/34
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To get back to the turbine:
I was told that Tesla invented this turbine and it could not be made to work well at his time for lack of materials. Today those materials exist and the technology for the turbine is SUPPOSED to be superior. There was some talk about superhigh revolutions that could not be managed with materials of Tesla's time. I gather they were talking about larger turbines than the one mentioned in the post above.
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The Tesla turbine seems simple...
..What do you think? What is the great benefit if there is one?
Well there is this (NSFW)!!!!:
http://ladycartoonist.com/archives/34
Where are the tubes that allow the gases to flow into the turbine? How are they exhausted in a way that is not distracting to the user? This is not a "cordless" device, I assume. Does the vibrator not get rather hot when operated with steam?
Nice machining job though.
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I presume that the steam goes in at the little plug thing on the side and out through the vents.
It would be a bit scary though with steam like that I would think. Compressed air could be more appropriate.
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wolfekeeper:
The spark transmitter.
How would Tesla have measured the "High Q" of his resonator if he hadn't access to cw oscillators? If you don't use an active device (valve etc) and a good filter / matching sircuit I can't see how you would get narrow bandwidth plus reasonable power out of a transmitter. What was the state of filter design in those days? The maximum frequency used for his experiments would have had to be in the order of hundreds of kHz. You'd be lucky to get more than a couple of channels to work over a useful distance without mututal interference problems.
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wolfekeeper:
The spark transmitter.
How would Tesla have measured the "High Q" of his resonator if he hadn't access to cw oscillators?
It's not that difficult to calculate. Inductance, resistance and capacitance. Heard of them? Tesla had. I don't know how he did it, but you can measure currents using coils and magnetism; it's usually called a 'meter'.
If you don't use an active device (valve etc) and a good filter / matching sircuit I can't see how you would get narrow bandwidth plus reasonable power out of a transmitter.
I'm sure it was pretty inefficient, but it doesn't matter.
What was the state of filter design in those days?
Tesla was the state of filter design in those days!
The maximum frequency used for his experiments would have had to be in the order of hundreds of kHz.
Yup, his Tesla coils were up to a few meg.
You'd be lucky to get more than a couple of channels to work over a useful distance without mututal interference problems.
A lot of his stuff did have *very* high Q, so not as bad as you might think.
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Efficiency isn't all that counts - it's actual Power! He didn't have many hundreds of Watts of DC available (ok, perhaps 1kW) and the 'coherer', which was all they had as a detector, was pretty insensitive. The only thing in his favour would have been the lack of other transmitters to interfere with his experiments.
Measuring Q: Yeah but if you haven't worked out the effect Radiation Resistance of the antenna, how can you tell what the resistance (gives Q) is? You can't just measure the DC resistance - that's an entirely different thing. Even now, you have to do it numerically for RF inductors.
Sorry, but, techincally, you are into the realms of farmyard products. To "RF with a "meter" you need a diode - did he have thermionic diodes? No. He had to use a coherer.
Tesla was the state of filter design in those days!
That's not an answer. I was interested to know what the actual state of knowledge was. Filter theory is actually quite a recent development. (First World War ish)
Why does he have to have been a superman? Don't make out he had done everything. Get him into perspective.
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Efficiency isn't all that counts - it's actual Power! He didn't have many hundreds of Watts of DC available (ok, perhaps 1kW) and the 'coherer', which was all they had as a detector, was pretty insensitive. The only thing in his favour would have been the lack of other transmitters to interfere with his experiments.
Measuring Q: Yeah but if you haven't worked out the effect Radiation Resistance if the antenna, how can you tell what the resistance (gives Q) is? You can't just measure the DC resistance - that's an entirely different thing. Even now, you have to do it numerically for RF inductors.
Tesla is known as somebody who actually measured skin effect. Gee I wonder why/how he did that?
Sorry, but, techincally, you are into the realms of farmyard products. To "RF with a "meter" you need a diode - did he have thermionic diodes? No. He had to use a coherer.
No, he also had spark gaps. You can get a very good idea of voltage and resonance with calibrated spark gaps.
You keep jumping to these fantastic conclusions; like to measure X, you need a digital multimetre, and there's no other way to measure it!!!! Therefore he's a crank... blah blah blah.
Really, there is more than one way to skin a cat. Just because you know only one way, doesn't mean that's the only way.
Tesla was the state of filter design in those days!
That's not an answer. I was interested to know what the actual state of knowledge was. Filter theory is actually quite a recent development. (First World War ish)
Well, probably in the full glory. But Tesla knew from mechanical experiments quite a bit about resonance. I read about how he would set different pendulums swinging and stuff like that. I'm sure he wouldn't have been able to work out the interference between two tuned circuits, but then again, he could build two circuits and try it.
Why does he have to have been a superman? Don't make out he had done everything. Get him into perspective.
I'm the one that has got him in perspective. You're the one that's accusing him of being a talentless quack that never did anything worthwhile. Anything that he actually did, you claim that it was impossible, that there's no way to do, that it was all made up.
To build a Tesla coil, you primarily need a couple of tuned coil with high Q (a few hundred). He invented this. He didn't just do it by sheer luck. Your attitude that he couldn't have done it, is really, very, very funny indeed.
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"calibrated spark gaps" eh?
I guess they would be very frequency sensitive. Their striking voltage at DC could be different from the voltage at 1MHz. They would, undoubtedly work 'in principle' but what point are you trying to make? No one uses them now because they aren't very good. They were a first stab at the problem- that's all.
Didi you take my point about measuring Q at RF?
Who mentioned a Digital Multimeter? They have only been around for a few decades and no better in principle, than a good moving coil meter for many applications.
I never said that Tesla didn't invent the Tesla Coil. That would have been daft, wouldn't it? I said that the spark communication system did nothing more than prove a point.
He may well have been able to detect a spark transmitter radiating a short distance away using a resonant circuit. If that constitutes a useful form of communication, then well done to him.
The point about spark transmissions is that the transmitted signal, by its very nature, is broad spectrum. If you use a narrow transmit filter (to avoid putting out interference) then you reduce the transmitted power pro-rata. It rapidly becomes less and less worth while to use the technique, the more channels you want to use. It's classic communication theory.
The output filter for a transmitter using a carrier wave can be very sloppy because the power spectrum is defined by the drive oscillator. I'm not sure what the argument is all about.
Looking through my posts I can't find the words "talentless" or "quack". Where did you read them?
I have no argument at all with the dear Nicola. My argument is with the fan club who want him to be the Messiah and not a very naughty boy.
Why go for Tesla when there are names like Helmoltz and Heaviside (contemporaries of his) whose formulae and principles are still in daily use? They gave him a Unit in his honour, what more do you want?
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I can find no reference to spark gaps being frequency sensitive. Do you have a reference?
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No particular reference, it's just that, in general, the ionisation of a gas and the fields around an object are sensitive to frequency. The striking voltage would certainly be related to a combination of peak field, mean field, and recombination rates. You couldn't be sure of your calibration. But, I'm sure Tesla had an idea about that and would have treated his measurements more realistically than his enthusiastic followers have, apparently.
You see, as he wouldn't have had access to a signal generator, he would need to have been using narrow band filtered spark signals (effectively, noise) to explore the characteristic of his wider band filter. Personally, I can't see that he would have had any accurate idea of the Qs involved. To predict the Q of a resonant circuit coupled to a radiator, you actually have to know how much energy is being radiated - to give the radiation resistance. For anything other than a half wave dipole this is difficult and this, amongst other things, makes me doubt that he would have known (or cared) too much about the finer points of his experiment. I don't know what the state of antenna theory was when he was using sparks - pretty poor I imagine - there were no antennae which needed analysing until people started using proper transmitters!
He achieved 'wireless' transfer of energy / information in the only way he had available at the time. I have never said that was not a good thing. I have always said that it needs to be seen in proportion. To do that, it may be necessary to know a bit about RF Engineering since his time.
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You see, as he wouldn't have had access to a signal generator, he would need to have been using narrow band filtered spark signals (effectively, noise)
The words you're looking for is 'impulse response' A spark is an impulse.
to explore the characteristic of his wider band filter. Personally, I can't see that he would have had any accurate idea of the Qs involved.
You know what? Dunno. And I am completely sure you don't know either what he could and couldn't do, given the technology of the day.
But, given what he did achieve, building powerful Tesla coils, he did indeed achieve high Q; and using his Tesla coils it would have been very obvious when Q went up, and Q went down.
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An how do you suppose Mr Tesla would have measured the "impulse response"? Accurate time domain analysis at RF didn't come into the picture until they invented the Oscilloscope.
In fact, he used continuous sparks, didn't he? That is a very rough type of noise. Rather hard to analyse at all, actually.
I am not sure whether you appreciate what Q means. It represents the rate of power loss compared with the reactive power in the circuit. If you want to extract power out of a resonator, you can't have a high Q - because Q is an inverse measure of the energy leaking out. Before the corona starts at the top of the Tesla Coil, the system has a higher Q than it does once it has started.
I just remember that, when I used a transmitting valve as the power source for a Tesla Transformer, then it was delivering very impressive arcing, the valve used to nearly melt itself. The coupling with the outside was very much affecting the transformer circuit. It would have been the same with the primitive spark design.
Just because we have no direct evidence about what he measured an how, we have no reason to assume that he was doing anything particularly accurate. It would not have mattered for the purposes of producing his demos.
What "power" did his "powerful" coils produce? Do you know? In a darkened room with the right stage management, a moderate spark could have looked pretty impressive.
What was his primary power source?
But you said it all with your "given the technology of the day" phrase. He did what he could and no more.
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An how do you suppose Mr Tesla would have measured the "impulse response"?
I don't think he did. The scientific position is that macroscopic systems like impulse responses exist whether or not you measure them.
In fact, he used continuous sparks, didn't he?
No, all Tesla coils use an intermittent breaker system.
That is a very rough type of noise.
No. Tesla coils are driven by impulsive excitation.
I am not sure whether you appreciate what Q means. It represents the rate of power loss compared with the reactive power in the circuit.
Really? I wasn't aware of that. At all. Thank you for sharing your awesome knowledge. No, really. I mean it. Honest. Thanks.
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His sparks could not have been 'impulses' they were bursts of energy, from some form of induction device, which would involve an LC resonance - the classic Rumkorff(?) induction coil, no doubt, but beefed up. He would have been using bursts of very mucky RF (bursts if noise modulated carrier, would be one way of looking at it) from his exciter. He was stuck with this rather than cw because he didn't have a Valve to use. With a cw transmitter to drive the primary, you get a cleaner spectrum and much better performance. The coil is still a 'tesla coil' - it's just a more modern incarnation.
Why introduce the term "impulse response" as if it was relevant to Tesla's measurement capabilities. I don't see, remotely, how it could have been.
A good example of how to get an indication of the Q of an oscillator is to count the number of swings of a pendulum to where they get to 1/e of their original amplitude. (i.e. half energy). Fine with slow mechanical oscillations but harder to do with a burst of RF. You can see it on an oscilloscope though, for a resonant RC circuit, when you disconnect it from its exciter oscillator.
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A big advantage of Tesla turbine is cost and simplicity. But, in spite of the fact that turbine consists of a set of smooth disks; efficacy of turbine depends on spacing between disks. Spacing between disks has to be as close as possible because a fluid drags on the disk by means of viscosity and the adhesion of the surface layer of the fluid. Typical gap is less than 0.5mm that means the disks have to be extremely smooth and spacers between disks have to be very precision too.
To my mind, it would be easier to make turbine with two cones – see attached pictures. Such turbine also works by means of viscosity and the adhesion of the surface. But, in contrast to Tesla’s turbine, such turbine has self-alignment gap. If there is not fluid between cones then gap is zero. When we are feeding turbine with fluid then inner cone is going up and revolving. Also such turbine doesn’t have problem with bearings because it steams over a fluid.
To get electricity, permanents magnets can be inserted in inner cone.
As example, I built very simple prototype which can be made in 5min. For this you need 2 flowerpots and air from vacuum cleaner. You can watch it on my video.
Also if we have bigger air pressure then we can decrease gap by setting heavier inner cone that gives more power. Also surface of cones has an influence on lifting force because force depends on air pressure and the surface on which the air presses.
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I believe that spark transmitters were employed in some German anti aircraft radars in the 1940,s
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Tesla turbine was a rotary design which with the use of disks reduced the shock of the blade because the attack was parallel and not a steep angle. Adhesion is the force that was used and not the standard push, pull. No vibrations meant that maintenance was easy and the ability to adhere the substance used made for a quiet run. Very efficient.
Tesla was quite possibly one of most intelligent people our planet has seen and if JP Morgan was not involved we would all be using free electricity right now. The wireless transmission of power that was collected from our stratosphere means all would prosper. Evil men can't make slaves of the world this way. Patent or no patent when men have the method but hide it so they can make money must stop. Kind of like the Federal Reserve. Useless and must be abolished.
Haarp is now the weapon in use from the Tesla Tower. Leave it to evil to use good for bad
"Evil succeeds when good men do nothing"