Permanent magnets and magnetic energy

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Hello

I am new in this forum and also my knowledge on physics is not very good.
Now i am trying to understand how the permanent magnets work. We know that if we take ferromagnetic materials and by doing a specific process we can create a magnet. Then by subjecting the magnet into a high electromagnetic fields the magnet becomes permanent magnet. Correct?
Also, according to my findings on the web everyone says that the permanent magnets cannot be assumed as a source of energy, and my question is why?
When we create a magnet we have to put some energy in order to make the magnet material permanent magnet, so where does this energy goes? Why after the magnetization the permanent magnet offers "infinitely" magnetic field? Does this magnetic field is the energy (i.e. magnetic energy) from permanent magnet? if yes how comes the magnet is not assumed to be a source of energy...
However, up to this point i make a very simple example in my mind which is probably wrong but is what i see in reality. So i relate a conventional rechargeable battery with a "permanent magnet". So, a fully charged battery is assumed to be a source of energy (i.e. electrical energy) so it can be used in a lot of applications, but when the battery is discharged we have to recharged it in order to use the battery again. In addition, we know that a "permanent magnet" at some point in time its magnetic intensity (or magnetic properties) becomes weaker or may be close to zero, therefore the magnet has to be re-magnetized in order to be able to used it again.
So, from the above the above example i can obtain that a rechargeable battery and a "permanent magnet" have more or less the same function, i.e. charged and discharged. So why the permanent magnets can not be assumed as a source of let say magnetic energy, what is the mathematical proof for that?

I am getting confused with that :confused: , and when i try to answer one question to myself and another questions arise....... :frown:

So, is there any very good book that i go and buy which it can explain to me this subject? OR is there any good sources like web links or anything that i can look at it?

Thanks in advance for your time.

Kind regards
A.M.K
 

Answers and Replies

  • #2
Drakkith
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Permanent magnets by themselves cannot be used as a source of energy. This is the same as the gravity of the earth being used as energy. We DO use gravity as a source of energy, for example in Hydroelctric plants, but that is because the Sun provides the energy to cause the water to evaporate and eventually fall back down, refilling the resevoir. Without the sun you would not be able to get renewable source of energy out of the plant.

In the same way, we DO use magnets as a source of energy in electrical generators. However we must have a source of energy to do work to make those magnets produce power.
 
  • #3
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Hello Drakkith and thank you for your reply.
Just today i found on this forum something similar to my post above related to permanent magnets, and the post was something like "how the magnets work" and on this topic no one was able to explain how the magnets actually work.
And i think in order to answer my question "if we can assume a magnet as a source of energy (i.e. magnetic energy)", we have to first understand how the magnets work.
So can anyone have the knowledge to explain how the magnets actually work? I will really appreciate it!!!!!!!

Thanks in advance for your time.

Kind Regards
A.M.K
 
  • #4
Drakkith
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From wikipedia's article on Magnetism:

In magnetic materials, sources of magnetization are the electrons' orbital angular motion around the nucleus, and the electrons' intrinsic magnetic moment (see electron magnetic dipole moment). The other sources of magnetism are the nuclear magnetic moments of the nuclei in the material which are typically thousands of times smaller than the electrons' magnetic moments, so they are negligible in the context of the magnetization of materials. Nuclear magnetic moments are important in other contexts, particularly in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI).

Ordinarily, the enormous number of electrons in a material are arranged such that their magnetic moments (both orbital and intrinsic) cancel out. This is due, to some extent, to electrons combining into pairs with opposite intrinsic magnetic moments as a result of the Pauli exclusion principle (see electron configuration), or combining into filled subshells with zero net orbital motion. In both cases, the electron arrangement is so as to exactly cancel the magnetic moments from each electron. Moreover, even when the electron configuration is such that there are unpaired electrons and/or non-filled subshells, it is often the case that the various electrons in the solid will contribute magnetic moments that point in different, random directions, so that the material will not be magnetic.

However, sometimes — either spontaneously, or owing to an applied external magnetic field — each of the electron magnetic moments will be, on average, lined up. Then the material can produce a net total magnetic field, which can potentially be quite strong.

The magnetic behavior of a material depends on its structure, particularly its electron configuration, for the reasons mentioned above, and also on the temperature. At high temperatures, random thermal motion makes it more difficult for the electrons to maintain alignment.


In other words, the electrons orbit around their atoms give rise to a magnetic field. Normally these cancel out completely. Sometimes a material is able to have its electrons line up so that all the poles of these "little magnets" line up. You also need the larger structure of the material to be lined up correctly as well, otherwise you have small "sections" of a larger object where each section is lined up inside itself, but is oriented so that it cancels out another section. If everything lines up correctly you get a permanent magnet.
 
  • #5
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So inside the magnet, the mechanism that maintain the magnetic field around the magnet are the lined up electrons? Because i can not understand how the electrons exist in a permanent magnet....... if it was the electrons that maintain the magnetic field on a magnet, so the magnets can produce electricity somehow????? :uhh:

I can understand the principle of the electromagnet where a wire i connected to a source let say a battery and hence the electrons flow through the wire and therefore magnetic field is created around the wire...... but on a permanent magnet i can not "see" any electrons flow or something like that........

Thanks for you time

Kind regards
A.M.K
 
  • #6
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No one knows how a magnet works. there is no current explanation of how any field works. we do not know how particles interact, and must utilize tools such as virtual photons to get to the point where we can model that type of behavior.

however, the mechanics of magnetic systems are well understood, and the above posters have given you some good information and suggested reading regarding why a magnet cannot be used as an energy source.
 
  • #7
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hello guys and thank you all for your responses, but this is where i want to conclude, because we do not know how a magnet works, i think we can not say that the magnet cannot be used as a source of energy.
This is my opinion up to this point. However, i really appreciate the existing theory of how the magnets and magnetism work.

Thanks for your time.

Kind Regards
A.M.K
 
  • #8
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i can not understand how the electrons exist in a permanent magnet...

on a permanent magnet i can not "see" any electrons flow or something like that
How much quantum mechanics do you know? Do you know what orbital angular momentum is, and do you understand the concepts of the Pauli exclusion principle and unpaired electrons? Do you know what an intrinsic magnetic moment is?

this is where i want to conclude, because we do not know how a magnet works, i think we can not say that the magnet cannot be used as a source of energy.
You may want to take more than 18 hours to learn before making a rash conclusion like this.

We do know how magnets work. It's interaction with other EM fields is well-explained by Maxwell's equations, and the source of ferro-magnetism is well-explained by QM. There is, to date, no EM phenomenon which has been observed which is not explained by QED.

Magnets cannot be used as a source of energy. They can be used in generators which transform mechanical energy to electrical energy, but they are not the source of the energy. They can also be used as energy storage devices, but again they are not the source of the energy. The energy in a magnetic field is well understood and is conserved:

http://farside.ph.utexas.edu/teaching/em/lectures/node89.html
 
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  • #9
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Dear DaleSpam,
thank you for your reply, but at the beginning of the topic i mention that my knowledge on physics is not very good. That's why i am here, to get an explanation and thus to solve my queries.
Also in my very first post i say if anyone knows a very good book to purchase, because i am a book buyer, but no one make this.
In your reply you say about how much quantum mechanics i know, the answer is very very little, that's why i am asking for help and some good suggestions on books or any other web sources.


thanks for your time

kind regards
A.M.K
 
  • #10
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at the beginning of the topic i mention that my knowledge on physics is not very good. That's why i am here, to get an explanation and thus to solve my queries.
Also in my very first post i say if anyone knows a very good book to purchase, because i am a book buyer, but no one make this.
OK, are you familiar with classical mechanics including Maxwell's equations and classical EM?
 
  • #11
Drakkith
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So inside the magnet, the mechanism that maintain the magnetic field around the magnet are the lined up electrons? Because i can not understand how the electrons exist in a permanent magnet....... if it was the electrons that maintain the magnetic field on a magnet, so the magnets can produce electricity somehow????? :uhh:

I can understand the principle of the electromagnet where a wire i connected to a source let say a battery and hence the electrons flow through the wire and therefore magnetic field is created around the wire...... but on a permanent magnet i can not "see" any electrons flow or something like that........

Thanks for you time

Kind regards
A.M.K
Electrons are a subatomic particle that makes up ALL atoms. Every single atom in a magnet has multiple electrons in orbitals around the nucleus of the atom. Electrons also have "spin" that is intrinsic. That means that they ALWAYS "spin". This doesn't require anything to make them spin, it is just a property of the particle just like the mass and charge of an electron is. This spin, plus the movement of the electron around the atom generates a magnetic field. When trillions upon trillions of these line up like they do in a magnet you get a powerful magnetic field.

Note that this does NOT mean that there is a CURRENT in the magnet. The electrons are not moving between atoms in an ordered motion like they do in an electrical circuit.
 
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  • #12
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To DaleSpam,
I am an average user i can say but i now i prefer to make a new start because i think i make something wrong...so if you are planning to suggest any book i prefer books which are more descriptive rather than more mathematical. But anw i will appreciate it as well if the book is more mathematical, because, all in all you need maths everywhere.... :)

To Drakkith,
Is that the same happen with the Earth's magnetic field? So the magnetic field is energy (i.e. magnetic energy) ?
 
  • #13
Drakkith
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The Earths magnetic field is generated (as far as we know currently) by a Dynamo effect in the core/mantle. Look up Dynamo Effect on wikipedia for more info on that.
 
  • #14
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Heh sorry i say it wrong, i just wanted to say that the earth i moving around the sun and also around its self axis, like electron, but is not an electron.... :)
 
  • #15
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Is that the same happen with the Earth's magnetic field? So the magnetic field is energy (i.e. magnetic energy) ?
It might help to go back a few steps in the explanation. I do this, though, at the risk of insulting your intelligence by making it too simple. The previous posters were notably trying to avoid that, and I apologize if I am taking this back too far.

Whenever a force is applied through a distance, work is done. When you lift a stone, for example, you pull upwards with a force that about equals the stone's weight. To find the amount of work, you multiply the force by the distance you lifted.

If you simply hold the stone, you are applying a force equal to the weight of the stone, but not through any distance. In other words, the distance is zero, and the work done is zero.

Last step: energy is defined as the ability to do work. The lifted stone has energy because you could drop it on something like your foot and it will apply a force through a distance.

So if I take a compass and push the needle so that it no longer points north, I do work to the needle. That work is now stored in the needle and we call it "potential energy". The needle swings back to point north when I let it go, and the it potential energy I gave it is converted in the energy of motion ("kinetic energy"). (Realistically, some of the energy is also converted into heat from the needle rubbing against its pivot and from the needle pushing air out of the way.) Can you see that the magnetic fields of the Earth and of the compass converted potential energy to kinetic, but were not a source of energy?

Similarly, you could take two magnets stuck to each other and pull them apart. That requires you to do work, giving them potential energy with respect to each other. If you release them, they fly back together. That is the potential energy you put in getting converted to kinetic energy. Again, magnetism is not the source of energy. You are.

This why the previous posters say that magnetism (no matter how it works) is not an energy source.
 
  • #16
Drakkith
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Heh sorry i say it wrong, i just wanted to say that the earth i moving around the sun and also around its self axis, like electron, but is not an electron.... :)
That's semi-correct. The spin of an electron is not quite like the earth spinning. It's a little wierd, as it has a spin of 1/2, meaning that it has to spin around twice to get back to it's starting point. (It's wierd, look at Quantum Mechanics for an explanation). Also the electrons in orbitals are not little balls just circling around the nucleus like most pictures portray it as. They have complicated probability paths and their orbitals can get very complicated. But there are similarities. :biggrin:
 
  • #17
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thanks guys for explanation, i appreciate that!!!
I will go for coffee now, i will start studying QM from the beginning for my better understanding ......... :)

cheers
 
  • #18
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To DaleSpam,
I am an average user i can say but i now i prefer to make a new start because i think i make something wrong...so if you are planning to suggest any book i prefer books which are more descriptive rather than more mathematical. But anw i will appreciate it as well if the book is more mathematical, because, all in all you need maths everywhere.... :)
I would start here for some good overviews:
https://www.physicsforums.com/showthread.php?t=220911 [Broken]
http://www.etsu.edu/physics/lutter/courses/phys2020/index.htm
https://www.physicsforums.com/showthread.php?t=115340 [Broken]
 
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  • #19
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Hold on, is it possible?

Well, I think it depends on the type of energy you are talking about. While we can't expressly say that a magnet does work, we can't refute that there is some energy involved in maintaining the magnetic field. The magnet itself if motionless does no work, since no distance is moved, however, the electrons that are contributing to the magnetic field are in motion and are techinically doing work. Classical mechanics would lead us to believe that these electrons should one day stop moving and collapse to the nucleus however this is clearly not the case. The main theory as to why this is so is that there is an exchange of virtual photons that keep the electrons at a minimum distance from the nucleus. These "supply" the energy to keep the electrons in "orbit". Of course other disturbances such as EM waves and quantum fluctuations contribute to energizing the electron. It is therefore true if you say that there is a certain amount of energy being used up that results in a magnetic field. Of course we also have to consider that a magnetic field and an electric field are related by relativity, and in short, a magnetic field is a transformation of the electric field under the equations of relativity, i.e. length contraction.

Well what am trying to say is that it is possible to design a system to convert the minute fluctuation in the magnetic field brought about by excitations in the electron providing the field. Recently I heard of a research group that was able to detect the "noise" made when magnetic domains align and realign in a magnet. This detection is basically extracting energy through fluctuations in the magnetic field that is a result of the energetic nature of the domains. Well being possible doesn't make it feasible so whether it will happen is another story.
 
  • #20
Drakkith
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Well, I think it depends on the type of energy you are talking about. While we can't expressly say that a magnet does work, we can't refute that there is some energy involved in maintaining the magnetic field.
Yes we can. There is no energy involved in maintaining a magnetic field from a permanent magnet. The reason is because the magnetic field comes from the intrinsic spin of the electrons in the atoms of the metal. It requires no expenditure of energy to function.

The magnet itself if motionless does no work, since no distance is moved, however, the electrons that are contributing to the magnetic field are in motion and are techinically doing work.
No they are not. No energy is transferred anywhere, thus no work is done. Remember, work is NOT movement. Work is a force acting over a distance. An object in motion but without any forces acting on it is doing zero work.

Classical mechanics would lead us to believe that these electrons should one day stop moving and collapse to the nucleus however this is clearly not the case. The main theory as to why this is so is that there is an exchange of virtual photons that keep the electrons at a minimum distance from the nucleus. These "supply" the energy to keep the electrons in "orbit".
This is not correct. The electrons have a finite probability to be found absolutely anywhere, including INSIDE the nucleus. The virtual photons that mediate the EM force are not supplying any energy in this case.

If you'd like to know why an electron does not spiral down into the nucleus permanently, head over to the Quantum Physics forum and ask, as I don't know enough to explain it.

Of course other disturbances such as EM waves and quantum fluctuations contribute to energizing the electron. It is therefore true if you say that there is a certain amount of energy being used up that results in a magnetic field.
If the electron is energized, then it will be excited out of the ground state and into an excited one. But this has nothing to do with the magnetic field of a permanent magnet.

Well what am trying to say is that it is possible to design a system to convert the minute fluctuation in the magnetic field brought about by excitations in the electron providing the field.
No it is not. There is no such thing.

Recently I heard of a research group that was able to detect the "noise" made when magnetic domains align and realign in a magnet. This detection is basically extracting energy through fluctuations in the magnetic field that is a result of the energetic nature of the domains. Well being possible doesn't make it feasible so whether it will happen is another story.
If true, this is NOT related to anything you said above. The magnetic domains are sections of the metal where individual magnetic moments of the atoms are aligned with one another and they point in the same direction. I've never heard of what you're talking about, but if it's true all it's doing is taking the thermal energy of the magnet and converting it to something else, with the end result of lowering the temperature of the magnet. (I'm assuming thermal energy is where the energy these fluctuations in the domains comes from.)
 
  • #21
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Hello Gents,

After two years from my first post about that issue if the permanent magnets can be used as a source of energy, now i am able to say NO you can not use permanent magnets as a source of energy.

However, during all this time i was experimenting with permanent magnets and finally i have created a machine that can produce electrical power. The only info that i can post here is that the machine utilize permanent magnets along with a special configuration of coils. So, up to this point when the machine starts it continues running and i am able to extract about 30 watts of electrical power. Now, i will continue my experiments in order to find something which i will be able to extract more electrical power. The only advice that i can give to everyone is a quote from the biggest for my self inventor ever, Nikola Tesla.
“If you want to find the secrets of the universe, think in terms of energy, frequency and vibration.”

Finally, i would like to say a big thank to all the above people for their help and time which they was trying to explain me actually the theory of the permanent magnets.


Best Regards
Antonios Kallousias
 
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  • #22
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i was experimenting with permanent magnets and finally i have created a machine that can produce electrical power. The only info that i can post here is that the machine utilize permanent magnets along with a special configuration of coils.
Sounds like a standard generator:
http://en.wikipedia.org/wiki/Electric_generator

I cannot tell if you are excited because you built one yourself (in which case Congratulations!) or if you are excited because you think you invented something new (in which case I am sorry to point out that they already exist).
 
  • #23
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To DaleSpam

My friend I have finish the university at 2011 on the subject electrical machine and power electronics, so i know well what is standard generators etc. etc.
The one that i have make is running by itself, some people they call it perpetual motion machines, but i don not call it like that because is not a perpetual motion machine since if i will load the machine more than 30 watts is slowly running down and stops.
So, if you do not understand or if you do not accept the new products that people invent that your problem and not mine. Anyway, have a nice day....... :)

BR
A.M.K.
 
  • #24
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Hey , if you can prove your claims then I would like to see that.
Now before some mentor decides to close this thread, I would like to insist that we wait for AMK to give some schematics , numbers and drawings of the machine he has been talking about.You know how it goes in science , if you want people to believe you then you have to prove it someway.
Would you be so kind ?

Thanks.
 
  • #25
CWatters
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some people they call it perpetual motion machines, but i don not call it like that because is not a perpetual motion machine since if i will load the machine more than 30 watts is slowly running down and stops.
So your claim is that if you only extract 29W it will runs forever? So build 10, 100, 1000 or any number of your machines and you can draw as much power as you like. That is a claim to have built a perpetual motion machine and the moderators will be along soon to close this thread shortly.
 

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