Yet Another Perpetual Motion Device 563
The Star reports on this inventor breaking all the laws of physics as far as free energy goes. It even provoked interest from "esteemed Massachusetts Institute of Technology professor Markus Zahn". I would like to know how this seemingly backyard enthusiast's experimental set up has not been tried a million times over the years. It seems so simple and too good to be true. The article has links to a multi-part video demo of the device accelerating an electric motor under load for free!
So look at it, take it apart, spend a few minutes. (Score:2, Insightful)
Re:So look at it, take it apart, spend a few minut (Score:4, Informative)
Nothing to see here, move along.
Re:So look at it, take it apart, spend a few minut (Score:4, Funny)
Re:So look at it, take it apart, spend a few minut (Score:5, Interesting)
Wow, I'm almost cautiously excited. Call me stupid but I want to know more.
Re:So look at it, take it apart, spend a few minut (Score:4, Insightful)
Re:So look at it, take it apart, spend a few minut (Score:5, Interesting)
Actually, he never does cut power to the induction motor. He shorts or re-connects the electromagnet coils (that are part of the generator assembly).
What he demonstrates is that for the same or less power (Volts*Amps) of input to the motor driving the generator, he can cause the whole assembly to accelerate while using less power.
That is the interesting part (one more time): He can cause acceleration of the motor, while under a constant load, using less power.
Not a perpetual machine, but rather a really unusual way to get higher efficiency from a motor-generator assembly.
My concern is that in one of video parts (three I think), he shows a graph describing what he is doing in his experiments, and he shows a chart that has the constant speed/power line, a decelerating line (disconnected electromagnets) and the exponential acceleration line. He never tests it far enough -- and in the last part (or second last) he shows a plain split-phase induction motor and puts a small set of permanent magnets next to it. Notice that when he puts the small magnets next to the shaft of the motor it accelerates, but he keeps shutting the motor off to "prevent the shaft from getting magnetized". That may be the ultimate problem here, it might just be a short-lived affect from magnets. Once the whole assembly is magnetized, you don't gain any more from this effect.
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Re:So look at it, take it apart, spend a few minut (Score:5, Insightful)
I can do the same, by applying a brake for the first case, and not applying it for the second case. Now, if he shows that the first case's efficiency is close to 100% (with the brake), then we've got something noteworthy.
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Using a standard stepper motor which is essentially what he has here, the stepper motor can be timed to hit the Back EMF pulse in a position where it becomes a propulsion pulse. Typically the Back EMF pulse is proportional to the load on the motor. The result is that a forward kick equal to the RMS of the Back EMF pulse can be achieved. Since the motor rotated with force equal to the induced coil current less some losses like friction etc, the motor without the Back EMF pulse would be almost 100% effic
Induction Motor are Already Inefficient! (Score:5, Insightful)
Re:Induction Motor are Already Inefficient! (Score:4, Funny)
Re:Induction Motor are Already Inefficient! (Score:5, Interesting)
The company went bust because, although client companies who bought it saved up to 30% of their power, most did not want to know.
"We dont care about energy saving - it might break down, and then we would lose production."
It was not unreliable: It was used to mill the corn for a well known cornflake manufacturer ;->
There is a major problem getting people to buy energy saving in industry.
Its not much better in the domestic area. I later worked on domestic energy saving equipment which, here in the UK could alone save enough energy to meet the Kyoto treaty requirements. I got it working but the backers pulled out after a government backed Quango said "Ohms law does not apply in the UK"
Actual claims the inventor made (Score:3, Informative)
Symmetry (Score:5, Insightful)
But, here's the thing. The law of conservation of energy is derived from the inherent symmetry of the universe. Any system that live in a universe where the laws of physics are the same for left/right/up/down/front/back is doomed to be governed by fixed amount of over all energy.
But these are not absolute laws. If you manage to devise a pair of rings where what goes into one pops out the other with no change in temperature, you CAN create energy out of nothing. In fact, merely placing the rings at different altitudes will cause air pressure to generate a wind from the lower ring to the higher ring. You can easily use this wind to power a turbine, and you WILL get free energy.
Is the law of conservation of energy being broken here? No, it's just being subverted. The rings create asymmetry.
Of course, the opposite is also true. So long as symmetry was not broken, it is not required to delve into the details of the machine in order to conclude that it does not produce energy.
Shachar
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REALLY??? (Score:3, Insightful)
Quote: "The law of conservation of energy is derived from the inherent symmetry of the universe. Any system that live in a universe where the laws of physics are the same for left/right/up/down/front/back is doomed..."
You say that is NOT a claim that the universe is symmetrical? (Of course I did not mean physically symmetrical everywhere... that would be ridiculous.) But... "the inherent symmetry in the universe"?? And you claim that all the laws are the same
Re:REALLY??? (Score:5, Interesting)
Slashdot physics (Score:5, Informative)
None of this makes any sense. You're confusing energy with momentum. Air simply doesn't have "resistance to turning with Earth because of its gaseous state" and has no problem turning with the Earth.
These storms get their energy from the sun. In the more straightforward case of a hurricane, the sun is causing northward/southward movement by heating air at equatorial latitudes (and charging it with water vapor) more than the air closer to the poles (which stays cooler and drier). Due to the increased pressure the equatorial air moves toward the poles, and displaces colder air which moves toward the equator. (The water's heat of fusion helps maintain the pressure gradient by buffering thermal energy- it continues to heat the wet air as it moves poleward, and keeps the dry air cool as it crosses warm water which vaporizes and robs it of its heat.) The "Coriolis force" appears to cause circular motion, but it's a false force that's an artifact of the rotating coordinate system we like to use. In a non-rotating coordinate system, the air is retaining the linear easterly momentum that it had at the equator, so when it reaches higher latitudes it appears to be moving east, and the air that reaches the equator is now moving westward there simply because it had less easterly momentum to start with. Note that the Coriolis "force" does no work here since it applies itself in a perpendicular direction to the air's movement so the dot product is zero. Gravity, a real force, is doing no work here either for the same reason- even though it flips the sign of all linear momenta every 12 hours. All the work is being done by the pressure gradient.
The net effect is that the storm has had solar energy injected into it, which enables it to extract angular momentum from the Earth's rotation. When it reaches land and throws your stuff around, the Earth gets all its angular momentum back since the wind and debris is moving sideways with respect to the ground. The energy is dissipated in all the collisions into the form of heat, but the system's total angular momentum never changes.
Tornadoes are a bit more convoluted but essentially work the same way. Just like when I stir my coffee. I borrow angular momentum from the earth, with energy that originally came from the sun via the food I ate. As my coffee slows down, the earth gets its angular momentum back (transferred through the mug, through the table, and into the ground) and the energy I put into the coffee heats it and the mug it's in a tiny little bit. That energy came from the sun, not from the earth's rotation. I can't "draw power from the Earth's rotation" to stir my coffee unless I somehow hook my stirrer up to tides crashing at the beach. Those DO extract potentially useful energy from the angular momentum in the Earth-Moon system, since the Moon is available as an anchor and momentum can be dumped into it until the Earth and Moon eventually become tidally locked- analogous to the situation when a hurricane, tornado, or coffee stir is finally dissipated. At that point the angular momentum will be useless for extracting further energy.
Basically, you can't stick a generator axle into the North Pole and generate electricity by spinning the rotor. You have nothing to anchor the stator against.
Re:So look at it, take it apart, spend a few minut (Score:5, Insightful)
Re:So look at it, take it apart, spend a few minut (Score:5, Funny)
OK, but sarcasm aside, there is a tendency among those who teach science to put the Known Laws on an unassailable pedestal... largely in reaction to the rebellious students who refuse to believe anything they say.
Re:So look at it, take it apart, spend a few minut (Score:5, Insightful)
So how hard were these laws faught before it was the common standard taught to us?
These laws do not address where forces like magnets and gravity come into play and if they could ever be tapped or not. Just because they haven't been made into laws before doesn't preclude them from ever being added to the established laws as footnotes. If we discover that the magnet like the sun degrades over time because it uses stored energy this would be all common place in a few generations and magnetic generators would be standard. If we learn to tap the constant pull from magnets and use them to create work but at the cost of the magnetic pull over time, this would stay within the "laws" and everybody would be fine with it. You use a resource until it's depleated and no one argues over it and claims that they are the greatest scientific voyer ever and can prove the underpinnings of the universe obey their assumptions and not the theories of others. Until ot was proven imagine someone claiming that they could take a gallon of liquid and move an object 30 miles. The energy stored in gasoline just had an easier method of extraction and left a more altered residual. Now take a rechargable battery in the tesla raodster that can move a vehicle a couple hundred miles and doesn't leave an empty tank, but a depleted battery that can be recharged with invisible electrons and go again without adding an observable amount of mass. This is no fantasy of the loose minded but a natural extension of the valid science applied in the persuit of extracting energy from material properties and interactions, fusion, nuculear reactions, charged states, magnetism. Just because we understand some part of our environment doesn't mean that we know the rules of the whole game. Black holes that have been discovered still don't follow the rules of thermodynamics since they absorb energy and do not release it in the same amount unless you count gravity as energy, which it that case you can't say that gravity will never let us convert it back to energy that we can use. The "Laws" don't address the one way principle that people like to use against these kinds of ideas to dismiss them. And just because poeple haven't done something before should be no excuse why some shouldn't try. Remember that every major scientific advancement was not done in the past, but the present for the experimenter. Before it was known and accepted. Not after everybody thought it was allowed.
Re:So look at it, take it apart, spend a few minut (Score:5, Informative)
typical slashdot (Score:5, Interesting)
Clearly the professors (Markus Zahn and at least one other) have studied the invention and cannot explain the result. You, on the other hand, based on cursory information, understand every little detail. So typically slashdot: I took a course in university on the subject, so my opinion is better than the professors.
Re:typical slashdot (Score:4, Insightful)
If he gives an evading answer, like "i cannot say anything from this, i need to examin it closer", the wonders of press will make a "Professor cannot explain what happens!!!1" out of it.
Scientists cannot explain != mysterious (Score:5, Insightful)
I'd be willing to bet that if you asked the professors off the record they would give you an explanation in the line of what the GP did, but they have to be more restrained in their public declarations. They are careful not to make public guesses about how it works, because, inevitably, they would be wrong about some small detail and the "inventor" would be able to say the scientists know nothing.
Or do you think scientists are so stupid that, after more than a hundred years of research, they would have overlooked a basic principle that a dyslexic cook can discover by himself? The scientists have not studied the invention at all, the only reason why they cannot explain the result is because they have insufficient information. It's not as if this guy had published the plans for his machine, all the professors could see was a demo presented by the inventor.
This guy seems to be crook who tries to do his job by letting the victims read between the lines. He has *wink, wink* NOT invented a perpetual motion engine, and he is *wink, wink* NOT after investments for "further development".
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Or do you think scientists are so stupid that, after more than a hundred years of research, they would have overlooked a basic principle that a dyslexic cook can discover by himself?
Umm... We need to be careful about that. We owe some pretty important physics to a dyslexic patent clerk. But, it's important to remember that a scientist is still a normal person. In the situation of a demonstration, they are just as easily deceived as a normal person - sometimes even more easily. Perpetual motion is an extraordinary claim, and requires extraordinary proof. In all cases it must be approached with great care and deliberation to avoid error.
Re:Scientists cannot explain != mysterious (Score:5, Informative)
Some quotes:
"they have demonstrated the Perepiteia to a number of labs and universities across North America, including the University of Virginia, Michigan State University, the University of Toronto and Queens University."
Prof. Habash of University of Ottawa looked at it: "It accelerates, but when it comes to an explanation, there is no backing theory for it. That's why we're consulting MIT. But at this time we can't support any claim."
Prof. Zahn of MIT: "It's an unusual phenomena I wouldn't have predicted in advance. But I saw it. It's real. Now I'm just trying to figure it out."
What I infer from this is that competent people have looked at it in some detail and were surprised, so it is possible that a new more efficient motor has been invented (it is also possible that some old forgotten motor is now more efficient because of new material, or any of a million possible outcomes.)
It is even possible that the professors forgot about magnetic brakes and other basic undergrad stuff; but I would not bet on that. It is also possible that this is a "con" but I also would not bet on that.
Some people seem very sure that this is non-sense. Would any of them like to give me 10-to-1 odds? That is, if turns out to be non-sense, I lose $1; it it turns out to be a more efficient motor, I win $10. (I will ignore the vanishingly small probability that it actually is revolutionary.) This means I am offering free money to people who are 100% sure. Even if you are only 95% sure, you still have positive expected value. On second thought, I have no desire to be jailed by some over-zealous police or DA when I am flying somewhere; so the bet will be for bragging rights only - no money.
Stanley Who? (Score:5, Informative)
Since you gave no link, I had to google that name [google.com]. Here's a good tip: when you read about an inventor who has trouble getting someone from the scientific community to look at his prototype, google on his name plus the word "fraud". Failing to do that, you risk being part of a notice like this [padrak.com]:
Groundbreaking changes don't come from the outside (Score:5, Insightful)
Many people seem to believe that, but it's not how science works. (Or even art, for that matter, Picasso took extensive training in classical art before he started his revolution in painting, for example...)
Look at any big breakthrough in science, it has never, ever, been done by an outsider. Big fundamental changes in the current thinking process always come from a scientist, usually young, who has thoroughly studied the subject before concluding a change is needed.
It's not that there is a "box" limiting scientific thought, but theories are created for specific sets of circumstances. When science and technology expands beyond those circumstances, new theories are needed. However, when you are creating new theories, it's never helpful to be ignorant of the current theories. You cannot circumvent the limitations of current theories if you don't even know those theories.
Re:So look at it, take it apart, spend a few minut (Score:5, Interesting)
The effects (Score:5, Interesting)
Skipping past the bitterness.
What is occurring here actually does make sense. There are several arrangements that can be used to make it occur. So far the pattern I have seen is the mere circle with an outlying magnet. Another option is made up of 15 magnets spaced inside the wheel instead of outside of it. They accelerate the outer wheel rapidly - much quicker - and make the entire unit easier to suspend within a vacuum between two plates. You can then place a coil outside the vacuum encased box, that is passive and generates electricity through the changing interior fields. The inner system is started by placing a single magnet briefly on the outside to start movement - after which the interior cascades out of its initial stability. The other magnets prevent it from finding stability again and the system accelerates until it instead reaches the next state of field stability at a set rotational speed.
A fun side effect is that the system also operates as a gyroscopic platter.
But, what happens after significant time? In the exterior-to-wheel scenarios the magnetic field eventually stabilizes. Outside of a vacuum it generally fails to stabilize because of minimal drag forces that cause it to essentially overheat and stop. This is a case of mechanical fault. Mechanical fault does not bar it from being "perpetual motion", but does reduce the long term functionality.
However. What happens with the interior-to-wheel scenarios? They also stabilize. However they stabilize within a rotating field. The EM field actually slows - but does not stop - and continues to rotate around the exterior generating energy through the coil.
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So why is this not perpetual energy and where is this energy coming from?
Magnets. It is a straight forward answer. It takes a lot of energy to polarize a magnetic material. Rather, to magnetize it. Magnetic materials over long use lose their polarization. Ultimately they neutralize or become very weak.
When you create a system like this the magnets are under constant force. After enough time one or more magnets depolarize and the system returns to static stability. However, because of the nature of magnets, this can take a significant amount of time.
Magnets store a lot of energy in an alternative form. They, rather efficiently, release that energy. Unfortunately, they do obey the basic laws of thermodynamics. Thus, less energy comes out of them than what went in.
You can think of a magnet like a funky capacitor. You can put a lot into it and you will get most of that back out, but you will not get all of it.
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So, what is the use of these systems? Stored energy. The problem is that magnets with sufficiently strong fields are not cheap and do not come readily. We could produce them, but we would be returned to the same problem of where do we get the original energy from to "charge"/magnetize the magnets.
How could we use this stored energy? Well, using the gyroscopic nature of the spinning platters, one option would be to place them within vehicles and use them for electrical charge to power the vehicle. Of course, you would have to shield the EM field to keep from having two cars snap together like a couple of magnets
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That's what should happen.
A coil of wire with 90 volts induced in it and open-circuited (0 amps) will dissipate 0 watts.
Assume the coil has an resistance of 1 ohm. When he short-circuits the coil, it looked like the induced voltage dropped to about 10 volts.
10 volts / 1 ohm = 10 amps
10 amps * 10 volts = 100 watts
Suddenly adding 100 watts of load to a motor should slow it down.
Re:So look at it, take it apart, spend a few minut (Score:2)
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If we're being pedantic, it's a speed, not a velocity. Velocity is a vector, speed + direction.
Re:So look at it, take it apart, spend a few minut (Score:4, Funny)
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I actually just learned that a subject can't be 1 (Score:4, Funny)
Well...does he or not?
Re:So look at it, take it apart, spend a few minut (Score:5, Funny)
I think, you shouldn't, use so, many commas, as it, makes it hard to, understand what you're, saying.
Yes, I think, you, are right, I, am starting, now at exactly this point in time to shift my role model from william shatner to james joyce that should work out ok what do you think yes that feels much better
Comment removed (Score:5, Funny)
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Re:So look at it, take it apart, spend a few minut (Score:5, Funny)
Re:So look at it, take it apart, spend a few minut (Score:5, Interesting)
- Move to a state where power companies have "buy-back" requirements.
- install device effectively taking you off grid and turning your home into a mini-power plant.
- profit.
Then slowly ramp up your basement power production until you're putting so much electricity back out to the grid that state regulators come to investigate you. If they never do, you can just use the profits to build ever larger plants until you ARE a power company, and then you'll have to talk to the state regulators whether you want to or not.Re:So look at it, take it apart, spend a few minut (Score:4, Funny)
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Re:So look at it, take it apart, spend a few minut (Score:4, Insightful)
Re:So look at it, take it apart, spend a few minut (Score:4, Informative)
Casimer Effect (Score:4, Insightful)
Just based on the article (Score:4, Insightful)
And the articles don't give enough details to judge much.
But so far, slashdot is the only article that talks about perpetual motion.
Re: (Score:2, Troll)
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Contrast (Score:4, Funny)
Connect the corpse of Beethoven... (Score:5, Funny)
Re:Connect the corpse of Beethoven... (Score:5, Funny)
P.S. If you must try this, make sure the cat is declawed.
Re:Connect the corpse of Beethoven... (Score:5, Funny)
Re:Connect the corpse of Beethoven... (Score:5, Funny)
One unfortunate side-effect is that in the mean time his symphonies begin disappearing. When pressed for an answer, Professor Zahn explains "Well of course. He's decomposing."
Re:Connect the corpse of Beethoven... (Score:5, Funny)
CD-Player plays Britney Spears songs over and over. Beethoven spins in his grave providing mechanical energy to generator.
You know your music really sucks when even deaf composers spin in their grave because of it.
Nobody's calling it "perpetual motion" (Score:5, Informative)
There's no talk of perpetual motion. No whisper of broken scientific laws or free energy. Zahn would never go there - at least not yet. But he does see the potential for making electric motors more efficient, and this itself is no small feat.
Why the headline, Taco?
Re:Nobody's calling it "perpetual motion" (Score:5, Informative)
In the very first paragraph, TFA states "he'll demonstrate an invention that appears - though he doesn't dare say it - to operate as a perpetual motion machine."
As for why "nobody's calling it" that, TFA answers that as well, with:
Seems straightforward enough. The guy believes (or wants others to believe) that he has made a perpetual motion machine, but calling it as much would result in his instant damning to the land of crackpots. So instead of claiming something widely considered impossible, he describes it as simply some sort of "very efficient" electric motor, a perfectly reasonable (if unlikely, given his background) idea.
Zero bandwidth transmitter (Score:4, Interesting)
Re:Zero bandwidth transmitter (Score:4, Informative)
Not to dismiss your remarks regarding that others may have also independently invented this sometime in the last 40 years (though I believe you're simply referring to civilian commercial use in the past few decades)...
But it would seem to take just a wee bit of effort of web research to demonstrate that various forms of this have been around a lot longer.
Goodness. Tesla patented a form of frequency hopping in 1900!!
Hedy Lamer is famous for being the woman who more or less invented and patented an early form of CDMA in 1940.
Granted, these things didn't have widespread civilian use and applications until the last few decades. But it seems strange to present your story the way you did. It would seem likely depending in his implementation that this chap couldn't have patented it in any case due to longstanding prior patents.
Furthermore, describing this as "zero bandwidth" really seems strange. I can certainly understand why engineers would have dismissed this. A more accurate description of spread spectrum would be "infinite bandwidth". That is why it's called SPREAD spectrum. It flattens out the wave in the frequency domain. Simply because the power in any given range drops to the noise floor isn't quite the same as it truly being zero bandwidth.
Re:Zero bandwidth transmitter (Score:4, Interesting)
I Don't Like This Article (Score:3, Informative)
The text of
Green Plug (Score:2)
Re:Green Plug (Score:4, Interesting)
A quick google search confirms that the Green Plug is no longer made because electrical motors produced in the last five years or so have been redesigned and now incorporate the same features as the plugs [sandiego.gov]. Not because they didn't work on old motors.
I read the article... (Score:5, Informative)
He also says it's *NOT* a perpetual motion machine. He's asking experts to explain him why that happened, and if it could turn into a way to make electrical generators more efficient.
Re:I read the article... (Score:5, Interesting)
If this is the case then expect the 'permanent' magnets to lose their magnetism over time, and if this magnetism was imparted to them from an industrial process (ie. they are not naturally magnetic) then the extra energy would be coming from the magnet factory's machinery.
It is still interesting, however, since such a method would be a way of storing energy, reducing the need for batteries. To be useful this technique would need to be measured in terms of extra energy imparted, magnet lifetime and whether the weight of the magnets would be better used to hold more batteries.
IAAPBIDHMTGO (I Am A Physicist But I Don't Have Much To Go On)
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I don't know if this explains the observed effect, but it is a plausible explanation. I just had to intervene because I hate people that are rude and stupid at the same time. Thank you.
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So from all I could gather he's claiming this thing produces a net output (yeah he won't state it that way, but I don't see what else he could be saying). It sounds like he's saying there's a large amount of energy coming from somewhere in a short period of time; i.e., this is not some wimpy effect only measurable with careful
Public Education (Score:2)
These days, we're wondering when the oil's going to run out, and we need to look to how we get the most energy out of our Sun and gravity - the only real sources of energy on this planet, all other sources being derivatives.
Why can't we have a more intelligent pub
very simple what to do (Score:2)
Energy in == energy out with no known exceptions.
Re: (Score:3, Interesting)
That's a little too harsh. There is always the remote change that one of these perpetual motion inventors stumbles across a new source of previously unusable energy.
That's doesn't make it a "perpetual motion" machine, but it could still be enormously useful.
Off the top of my head, I could imagine that the earth's magnetic field might be used as an energy source. Some unknown affect might convert subatomic particles to energy in special situations.
The bottom line i
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Total energy, yes, but all machines whose purpose is anything other than producing heat waste some. For non-heaters, energy in energy out.
2nd law. (Score:5, Insightful)
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I've tried to explain exactly that to a few people, but the addition of your Sun/Earth model makes your explanation crisp and concise.
Videos (Score:4, Informative)
a possible explanation (Score:5, Informative)
I will assume that the motor is a common DC motor with field on the stator, armature on the rotor. If the flux from the magnet he's holding near the shaft is canceling some of the flux from the field, then the motor will naturally speed up. The opposite effect is when you increase the flux from the field... the motor slows down.
All this talk of flux... (Score:2)
The right start (Score:2)
How this magnetic brake works (Score:5, Interesting)
After watching the videos (whew!) here's what seems to be happening.
The setup is an induction motor driving a magnetic brake. The brake has both permanent magnets and coils. With the coils unloaded, there's some braking effect, as you can see when he turns the magnet wheel by hand. With the coils shorted, the braking effect decreases. This seems backwards, because, usually, shorting a generator increases the mechanical load. That's why this guy thinks he has something.
There's a classic Physics 101 demo where you have a big conductive disk rotating between the poles of an electromagnet, and when you short the electromagnet, there's a huge drag on the disk and it stops. That's an eddy current brake, and it's the analogy this guy is depending on.
But, in fact, he's re-invented a known type of magnetic brake. This isn't an eddy current brake; the addition of permanent magnets makes it something else. A known something else.
Here's an example of such a permanent magnet brake [cst.com]. Note that "the brake is applied when the coil current is zero", just as with the "Perepiteia" device. This is backwards from most magnetic brakes. Here, the permanent magnets are providing the field for braking, and current in the coil overrides the permanent magnets. In the "Perepiteia" device, the coils act as generators and have current through them the magnet wheel is rotating and the coils are shorted. This effect requires a nonlinear magnetic steel, so this is non-trivial magnetically. But commercial electromagnetic simulation software can simulate this effect, so it's well understood physics. It's a rare enough technology that there's no accepted name for this type of brake.
Note that in the Perepiteia videos, he has to hand-start his wheel, even though it's being driven by an induction motor. That's because, with his setup, the brake drag is at max when the wheel is stationary. With the wheel stationary, there's no current in the coils, so there's nothing to override the permanent magnets. Once the wheel is turning, the coils generate some power and reduce the braking effect.
There's even a patent on the application of this principle to powered window blinds. See U.S. Patent #6,967,418. There, it's used to hold the blinds in place with power off.
I think there's something else going on (Score:5, Insightful)
I think you're missing an important part of the puzzle.
When I watched the video, I was struck by how the coil on the right doesn't have a pole piece on its far end to take the magnetic flux back to the permanent magnet wheel. Then I saw him demonstrate the difference between having a brass motor shaft and a steel shaft, and I had an inkling of what was going on.
An induction motor is a very complex device whose complexity is masked by its physical simplicity. The induction motor builds a rotating magnetic field in the rotor by inducing current flow into the aluminum rotor windings from the AC stator coil (as any power transformer does). The interaction between the induced field and the stator field causes the motor to turn. The rotor has specific requirements with regard to the shape of the windings to achieve maximum efficiency. Understanding the current flow and the magnetic flux is a job for theoretical experts (which I'm not).
Notice that the apparatus is mounted on a steel table. This provides a flux path from the motor housing to the black coil at the right end of the machine. The addition of his steel shaft has "completed the magnetic circuit" between this coil (an AC generator) and the induction motor rotor, which will do very interesting things to the magnetic field on the rotor! Especially since the field he generates is an AC field with what, 16 poles? I think he has a four pole 1750 RPM induction motor.
More on nonlinear magnetics (Score:4, Informative)
So I have been thwarted in understanding what "non-linear magnetic steel" is.
There are whole families of non-linear magnetic devices. Non-linear magnetic effects are used in saturable reactors [wikipedia.org] for motor control, magnetic amplifiers, and other AC electrical devices. You don't see those things much any more, because power semiconductors are now used instead, but the physics still works. Also see this explanation of magnetic hysteresis [gsu.edu], which is a related non-linear magnetic effect.
Consider a permanent magnet brake that relies on hysteresis effects to absorb energy. Reversing magnetic domains requires energy, which comes out as heat. Look at the figure "Variation in hysteresis curves" in this article [gsu.edu]. Maximum braking is achieved when the magnetic field is near the middle, wide parts of the curves. If you use a coil to apply a magnetic field that forces the material closer to saturation, or to cancel out the field from the permanent magnets, the braking effect decreases. That's probably what's going on with the "Perepiteia" device. Mild steels are in the midrange of magnetic materials; they are easy to saturate magnetically, which is why they make wimpy permanent magnets, but have moderate hysteresis, so they make inefficient transformer cores. For a magnetic brake, though, you want something in the midrange of magnetic materials, where the magnetic domains resist changing direction enough to generate heat, but don't resist so strongly that nothing happens, as in a strong magnet. I suspect that the "Perepiteia" device has coils wound on mild steel, and the braking energy is dumped into heating up those metal cores. (Here's more than you probably want to know about saturation and hysteresis in magnetic materials for transformer design. [mag-inc.com]).
I'm still not clear on whether the magnetic connection to the motor in the "Perepiteia" device really has much to do with this. But there's nothing mysterious about an electromagnetic brake that turns off when you short the coils. It's unusual, but known.
This isn't really my field, but I do have a classical EE degree, so I had to learn this stuff once.
He even got the name wrong! (Score:3, Informative)
I want James Randi for this (Score:3, Insightful)
For example, most voltage and current meters do no measurement of phase delay between the curent and the voltage. A bit of odd impedance in a motor can often affect its performance considerably by drawing more of the current when it's at the highest voltage and the maximum power is delivered to it, rather than wasting energy in conductive losses at low voltages. And oddball impedances can cause surprising loads to the sources of electrical power, which are not noticed unless you look carefully at the fuel consumption for the upstream generator or examine the electrical load with better instruments. The relevant phrase to look this up is "power factor correction".
Slashdot editors on crack again... (Score:3, Insightful)
So how do we get from that statement to the slashdot headline?
Too much crack? Had a bad month in ad revenue?
No Useful Output; Hysteresis Brake (Score:5, Informative)
The following are a couple of the better comments we received.
No Useful Output
On Feb. 6, 2008, Peter Lindemann, DSc, writes:
I have reviewed all seven video links. In all fairness, I would like to say that Thane has built some nice demonstrations and spent a lot of time running experiments. That said, the films show nothing important. First of all, the films do not show enough detailed information to evaluate the demonstrations. Second, no free energy is shown. In fact, the generators are never shown producing any useful outputs. They are either shown producing voltage in "open circuit" mode, or they are shown in "short circuit" mode, where the generated voltage drops below one volt. So, ZERO WATTS are produced in either case.
The changes in mechanical drag are due to changes in inductance and hysteresis. Back in the 1980's, both John Bedini and I independently worked with "variable reluctance" generators. We both saw that these designs work like an inverse to a standard induction generator. That is, they produce maximum drag in "open circuit" mode, and minimum drag in "short circuit" mode. John found that the point of maximum benefit in this situation is to charge a battery, where the impedance of the generator "sees" the battery as a "near short circuit". Under these circumstances, the generator free-wheels and the battery charges quickly.
Unfortunately, Thane is not showing any useful benefits from the generator output. So, there is no "efficiency" to calculate because there is no output!
The real problem with these demonstrations has to do with his motor drive. The motor driving his system is a single phase induction motor. This type of motor has almost zero starting torque, and only produces its rated power at rated speed. So, the rated speed of his motor is probably in the neighborhood of 1725 RPM. Running this motor in the 100 RPM range converts 98% of the input electric power to HEAT. He says he has a capacitor in the input circuit to the motor, but this is never shown in schematic, so we don't know how it is hooked up. If the capacitor is connected in SERIES with the motor winding, it will act as a current limiter, and skew the power factor of the motor towards reactive power. This is fine, IF you want to limit the mechanical power of the motor as well. If the capacitor is connected in PARALLEL with the motor winding, it will act to produce reactive power for the motor locally, and reduce the amount of power it draws from the wall. But again, this would only be significant at rated speed.
The effect he shows when a magnetic field is applied to the motor shaft would be undetectable if he was operating the motor correctly. It is a very weak effect. It is probably caused by the external magnetic field interfering with the induced magnetic field of the rotor. This would not happen if the motor coils were not being severely current limited and the rotor was not "slipping" severely in the rotating magnetic field of the stator.
My GUESS is that the capacitor is in SERIES with the motor winding. This will limit the current to the motor to a specific maximum. At the speeds he is running these motors, the only other mechanism to hold back the input current would be the resistance of the wire in the motor coils. If that is all he had, the motor would quickly over-heat and melt the insulation right off the wire. The fact that the motor is running hot is proved in the seventh film where a large black fan is shown blowing on the motor!
From the data presented, my best estimate of the efficiency of the demonstrations is that over 90% of the energy going into the motor is converted to heat. The changes in drag of the generators is standard behavior for variable reluctance topologies
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Re:the quote (Score:5, Interesting)
Cuz we all know that REAL scientists immediately understand something the moment they lay eyes on in?
Cuz you assume that the "prof." got scammed and is foolish for even entertaining the idea someone might have come up with something new?
Seriously, I don't get it, what part makes him a jackass?
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If the prof is a real scientist, his reaction is completely appropriate. Did he say anything about buying the idea that it's perpetual motion?
Sorry, but a jackass is someone who would dismiss an observed phenomenon out-of-hand without attempting to discover what's really going on. Remind you of anybody you saw in the mirror this morning?
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Re:Am I Missing Something? (Score:4, Informative)
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