The Naked Scientists

The Naked Scientists Forum

Author Topic: Will this magnetic piezoelectric device work as a generator?  (Read 15863 times)

Offline Yahya A. Sharif

  • Full Member
  • ***
  • Posts: 63
    • View Profile
« Last Edit: 08/09/2015 13:28:03 by Yahya »


 

Offline evan_au

  • Neilep Level Member
  • ******
  • Posts: 4123
  • Thanked: 245 times
    • View Profile
Re: The magnetic piezoelectric generator
« Reply #1 on: 27/05/2015 22:34:14 »
Quote from: Yahya
it has output work more than its input work
What matters is the efficiency:
  • the energy you can extract from the device, compared to the energy going in.
  • or the power you can extract from the device, compared to the power going in.
  • if you get more out than you put in, we call that a "perpetual motion machine of the first kind"
The principle of conservation of mass/energy suggests that no device can produce more energy than it consumes. This is a pretty high bar that demands more evidence than an explanation of a diagram.

Quote from: Yahya
12500 V  is huge
A device with an open-circuit voltage of 12500V delivers no power, so it has zero efficiency.

Piezo electric generators are effectively insulators, so they have a very high source impedance. They can deliver only very low currents, which translates into fairly low power levels (less than you put in).

Some of the input energy is converted to heat in the crystal, and some more is converted to fractures in the crystal structure. Even more is wasted as heat in the source and in the load.

 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8132
  • Thanked: 53 times
    • View Profile
yes the efficiency is more than 100% ...

Not possible , even Homer Simpson knows that ...

Quote
energy can be transformed from one form to another, but cannot be created or destroyed.
http://en.wikipedia.org/wiki/First_law_of_thermodynamics

Obtaining power from human-movement is very costly ...
http://news.cnet.com/8301-13512_3-9779334-23.html
« Last Edit: 28/05/2015 12:31:35 by RD »
 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8132
  • Thanked: 53 times
    • View Profile
this device has nothing to do with human movement it is a generator can be moved by many means.

Your device, nor any other, cannot multiply energy from any source, human or otherwise.

Force can be multiplied by machines, but energy cannot. Energy cannot be created (or destroyed) ... http://en.wikipedia.org/wiki/First_law_of_thermodynamics

You'll find like-minded individuals in "Over-unity" forums , but you're all* wasting your time.

[ * except the scammers there who sell suckers kits to build machines which allegedly defy the 1st law, they're raking in the cash ].
« Last Edit: 28/05/2015 13:57:35 by RD »
 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8132
  • Thanked: 53 times
    • View Profile
this device works, thus violates the first law of thermodynamics, there have been attempts through history to create energy and this is a successful one.

You are mistaken. There never has been, and never will be, a device which can make energy.

Apparently people will be perpetually-interested in the concept of perpetual-motion machines, but such "over unity" energy-making machines are impossible ... http://en.wikipedia.org/wiki/Perpetual_motion#Impossibility
« Last Edit: 28/05/2015 16:45:07 by RD »
 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8132
  • Thanked: 53 times
    • View Profile
..impossibility is not in science, every theory or law can be withdrawn

It's not like law enforced by humans which can be broken, it's a fundamental physical law : a law of nature which cannot be broken.

  it is the law of thermodynamics and not the law of Moses

You have your priorities wrong way round : the laws of Moses can be broken , the fundamental laws of physics cannot.

... people thought in the past that nothing heavier than air can fly

Can only be true of people who had never seen a bee, a bird or a bat.

Can you give an example of a natural process which makes energy ? : that would be proof-of-concept that such a thing is possible. If the known-universe has not come up with an energy-creating-system in billions of years, what makes you believe you can make such a thing ? , ( other than the Dunning-Kruger effect ).
« Last Edit: 28/05/2015 21:59:41 by RD »
 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8132
  • Thanked: 53 times
    • View Profile
this device is simple , and its functionality can be traced very easy as I showed in the nine steps ...
Each step has conversion losses : so a 100% efficiency from any device is not possible.  A hypothetical energy-generating device would have over 100% efficiency, ( a fantasy).

... every perpetual motion device has its flaws ...
True , as none of them has, or ever will, work as described ... http://en.wikipedia.org/wiki/Perpetual_motion
 
 So you're wasting your time trying to create one which does , ( you can't say we didn't warn you ).
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4716
  • Thanked: 154 times
  • life is too short to drink instant coffee
    • View Profile
As the device is so simple, why not make one and let us see the result?
 

Offline Colin2B

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1918
  • Thanked: 123 times
    • View Profile
how I will be able to measure the power of a small bulb?
You would do better to use a standard resistor and measure the current and voltage drop, a bulb is too imprecise resistance changes with temperature of filament.
 

Offline Colin2B

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1918
  • Thanked: 123 times
    • View Profile

will a standard resistance and current measuring be enough ? will I need a voltmeter or just an ammeter ?  I think I can apply this law : power=I^2 *R
Yes, or measure voltage drop and use V2/R.
Your main problem will be if you dont have a constant voltage. You might need to measure with an oscilloscope to see the exact waveform, as a meter wont react correctly - even set to AC a meter will expect a sinewave.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
If everything was made perfectly and perfectly rigid it would probably be quite efficient; but not over 100%.

The screw-case things include:

- any flexing in the mounts dissipates energy, things vibrate and take energy away. If they were perfectly lossless, this wouldn't be a problem... but:

- the piezo generator flexes slightly when it's generating; this behaves much like a flexure, but the energy goes into electrical energy, and you don't get this energy back again; it's gone into the electrical circuit and lost in resistance of the bulb or whatever you're driving. So the magnet has to actively get pushed down when repelled, and it has to actively get pulled back up when it's attracted, which takes energy. That slight difference causes drag associated with the generation, so you can't be 100% efficient.
« Last Edit: 02/07/2015 19:31:12 by wolfekeeper »
 

Offline Colin2B

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1918
  • Thanked: 123 times
    • View Profile

yes but this output electrical energy is more than the mechanical input energy.

I'll be waiting to see this. With some scepticism!
 

Offline chiralSPO

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1879
  • Thanked: 144 times
    • View Profile
conservation of energy

If your device actually produced energy, it would violate the first law of thermodynamics. If it produced no energy, but worked at 100% efficiency it would violate the second law of thermodynamics.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
So the magnet has to actively get pushed down when repelled, and it has to actively get pulled back up when it's attracted, which takes energy.
the magnet is always at equilibrium , the repel force is always equal to attraction force, the distances will always be the same while magnet 3 moves from left to right and all magnets are identical .
Nope. Piezoelectric crystals flex slightly when they generate electricity. This fact is used for quartz crystal; they set up a mechanical vibration in a thin-cut piezo quartz crystal, by driving it electrically.

The flexure is critical to how it works, it's impossible for it to generate energy if it doesn't move slightly; but as soon as it moves, it upsets the symmetry and your system is no longer 100% mechanically perfect; and it will grind to a halt.
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4716
  • Thanked: 154 times
  • life is too short to drink instant coffee
    • View Profile

does quantum mechanics depends on first law of thermodynamics ? what other physics realms depends on first law of thermodynamics?

There's no "dependence".

Quantum mechanics (QM) describes how very small systems (like atoms and molecules) work, and whilst it is theoretically possible to describe a big system (like a steam turbine) by quantum mechanics, it is impracticable an unnecessary to do so. All that matters is that whatever prediction we make by QM should degenerate to the observed behaviour of large systems as described by classical mechanics.

Large systems all appear to behave as though ruled by thermodynamics (TD). QM allows for local fluctuations that are not described by classical TD but when averaged over a large system and an observable time, QM again degenerates to TD.

Your proposed device is a large system.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile

Nope. Piezoelectric crystals flex slightly when they generate electricity. This fact is used for quartz crystal; they set up a mechanical vibration in a thin-cut piezo quartz crystal, by driving it electrically.

The flexure is critical to how it works, it's impossible for it to generate energy if it doesn't move slightly; but as soon as it moves, it upsets the symmetry and your system is no longer 100% mechanically perfect; and it will grind to a halt.
I think the change is 0.1 % of the volume of the crystal when it is pressed ,which may sound little distance to affect the magnets distance from each other and their equilibrium .
Yup, sounds about right. But that movement, small as it is, is completely central to how piezoelectric materials generate energy. And energy is force times distance, so we're not talking about the piezoelectric materials making much energy either.

Also, the thing you're missing is that piezoelectric materials are symmetric; a movement generates electricity, but also electricity causes movement; so when the circuit is using electricity, it's changing the shape of the piezoelectric materials. So the amount of asymmetry is proportional to how much power you're extracting.

And that's why it doesn't work.

There's no such thing as a free lunch.
« Last Edit: 05/07/2015 00:15:50 by wolfekeeper »
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
I was just wondering , what part of physics would be violated if such device worked.
most of it. there's a whole bunch of things that rely on the conservation of energy.
Also since the conservation law follows mathematically from the symmetry of the universe with respect to time, the whole lot would probabaly need to be re-written because time is involved in most of physics.
https://en.wikipedia.org/wiki/Noether's_theorem#Example_1:_Conservation_of_energy

To cut a long story short; if your idea works you will redefine time.
Or, to put it another way, since we have observed how time actually works, you idea is mathematically proven to be impossible.

Perhaps you should have checked on that before you spent the money on the magnets.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile

 And energy is force times distance, so we're not talking about the piezoelectric materials making much energy either.
I can increase  the force as I want by increasing the strength of the magnets and that won't affect the equilibrium, also I can increase the number of devices to generate more power moving them with the same little force.
Nope, the retarding force caused by the distortion of the piezoelectric materials is proportional to the strength of the magnets.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
Piezoelectric materials act like electrical pumps, as you mechanically squeeze them, they pump electrons around a circuit, (or they try to- if they're open circuit they won't move, unless they arc across.)

Like a pump, this means that they act as a mechanical damper reducing and opposing the motion of the magnets that are pushing on the magnets mounted on them; it takes work to pump those electrons, just like it takes work to pump up a bicycle tyre.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
No, of course it's not right.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
The repulsive pole of the moving magnet, as it moves onto the piezo; the piezo will go down under the force it applies, but as it goes past, it will not lift back up again until the opposite magnetic pole approaches; so the force going towards it is higher than the force going away- it's a net retarding force.

As the other pole approaches, the attractive force initially will be less, then the magnet will be pulled up, and then as it leaves it will have to apply more force to get away again, because the magnet is then closer.

The net effect is that the moving rotor needs a net force to be present in both parts of the cycle to generate energy.

Conservation of energy is not an optional thing in physics!
 

Offline Colin2B

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1918
  • Thanked: 123 times
    • View Profile
......also the efficiency of this device is more than the efficiency of the rotating electrical generator.
So, do we assume from that comment that you have built and tested the device and taken measurements?
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
Instead of building it in a straight line, why not build it in a circle and make a rotary piezoelectric generator?

It turns out that linear generators are less efficient because you get end effects.
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4716
  • Thanked: 154 times
  • life is too short to drink instant coffee
    • View Profile
Conservation of energy.
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
I think I took the wrong way for this thread by claiming that this is an energy from nothing device , I learned that it is not important for a device to be an energy from nothing device to be useful, so will this magnetic piezoelectric device work as a generator?

Badly.
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums