Why is it impossible?

Discussion in 'Physics' started by cpu_user, Jan 16, 2011.

  1. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    Greetings all! This is my first post. I did a brief search on this topic, but it didn't help in my search for an answer.

    The question: Why can't you use permanent magnets alone to make a perpetual magnet motor? The knee jerk response from the little bit of searching I have done was "...violation of the conservation of energy.", "...no free lunch.", etc. My all time favorite is some sort of assertion of a Lorentz force. Lay men's terms a charged particle experiences a force perpendicular to its velocity in a perpendicular B field. Since the force and the velocity aren't in the same direction work cannot be done. This may be the reason, but I cannot understand how it applies to bar magnets that are electrically neutral or close to neutral, ie no charge on them.

    In Irving M. Gottlieb's book Electric Motors and Control Techniques on page 9-10 he asserts that its a matter of "switching logic" that is keeping the perpetual motor from occurring and that maybe long winter evenings should be used to discover the correct switching order of the magnetic poles of permanent magnets.

    Is Mr. Gottlieb's assertion incorrect? If so, why? I don't see how someone's response such as "read a physics book" can help when I am sure people who have these questions have read or are reading them and still cannot find the appropriate E&M law that would keep permanent magnets from forming a perpetual motor.

    Please help me to understand why it's not possible. I have read many chapter's in Halladay & Resnick's physics book trying to discover the answer as to why some many people cannot tolerate the idea of perpetual motors with permanent magnets.


    Thanks
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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    Please read this post. It is this forum's position statement on the subject you have raised.

    hgmjr
     
  3. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    Thanks for the reply. I have read that section. I am not sure if my post applies to that section. I am not touting over unity or free energy. I am simply asking a physics question. I looked to that section as to why my thoughts are invalid, but I couldn't see an actual E&M law that would apply. The law of conservation of energy law, I concede too, on the thought of where is the energy coming from. Who is supplying the energy. My guess is the magnets in their creation had stored energy within them. I am simply trying to find the appropriate E&M law that would apply to settle this thought. Since E&M is a physics topic, I thought it would be okay to post here.
     
  4. shortbus

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    Sep 30, 2009
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    The words permanent magnet says it all. The poles are permanent, they can't be switched at will like a electro magnet. The energy to make a permanent magnet takes way more than the magnetic out put of the finished magnet.
     
  5. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    I am not sure, I understand your position. Is there an E&M law that you can state that would allow me to ponder your position.

    Your comment: The energy to make a permanent magnet takes way more than the magnetic out put of the finished magnet.

    I concede that, but once the magnet is made, it has a magnetic field coming out of it. What E&M law violates the idea of "switching logic" of many magnets interacting to cause perpetual motion?
     
  6. t06afre

    AAC Fanatic!

    May 11, 2009
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    Your question is in the scope of this forum. At least until some "energy nuts" force closing of this thread. Up to this day. Law of conservation of energy is still not proven wrong. Many people have tried but have failed. Included my self. Then I was a kid I invented/draw a electric car with a wind generator mounted on top. I planned to let wind generator charge the battery:rolleyes: The plans stayed on the drawing board. So no mony was wasted. If you are interested in that kind of stuff. You may look into it. But do not invest in ANY hardware. Everybody before you have failed, and none of them has become rich.
     
  7. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    T06AFRE,

    I am not looking for a free energy debate, I simply am trying to understand the physics behind the opposition. It seems that most opposer's of the idea stated vaguely assert it violates physics. Well okay, I accept that it violates physical laws, but which electrical and magnetic laws does it violate? Once that is stated, I can go back to the books and check their claim and it will put the matter to rest quantitatively.

    As for your car claim, wont the drag on the wind generator bring the car to rest? Or was this some sort of rhetoric?
     
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  8. t06afre

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    Well remember I was kid. And my plan was to use this wind generator to charge the battery in order to extend the range of car. Charge the battery on the run so to speak. In my plans I did not think about the fact that the energy need to spin my wind generator would have been taken from the battery. Then it comes to energy there are no such things as free energy. Some may say that wind generators and waterfalls are free energy. but even this energy comes from the sun. But as we speak is very slowly but for sure burning out.
     
  9. Wendy

    Moderator

    Mar 24, 2008
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    The basic reason why it isn't possible is entirely because it is about perpetual motion, or free energy. The exact mechanism isn't important, if in the end it violates Conservation of Energy it can not work.

    Why can't energy be made from nothingness? My analogy is simple, matter and energy are the same thing, they can and are converted from each other. People have no problem seeing that it is impossible to create an object, but can't link that concept to energy. If they are the same thing, then you can not create energy from nothing.
     
  10. shortbus

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    I guess I don't understand your 'switching logic'. A "hard" permanent magnet can not switch its poles after being made.

    A permanent magnet is not very magnetic until it is magnetized as the final step of its creation. Except Lodestone which is a very low magnetic substance.

    Alnico, ferro cobalt, neodymium and all other permanent magnets are made of powders that are exposed to a powerful magnetic field to make them a magnet. That field has to be more powerful than the end product to get the individual fields of the powder in line.

    You really should Google, making permanent magnets for more info.
     
  11. Wendy

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    Mar 24, 2008
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    Electromagnets take energy, even more to switch.

    Permanent magnets are just that, permanent.
     
  12. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    "Switching logic", the term used by Gottlieb in his book, I take to mean arrangement of magnetic poles in order maintain continuous rotation. Two similar magnetic poles repel each other and such if these permanent magnets were place on a pivot point would cause a torque and thus a possible rotation. So again what Electromagnetic Law would negate this action from occurring until there no longer magnetic fields to oppose each other? I know you guy's understand what I mean. I am not trying to be funny, I am simply trying to justify the claim that it can't work with something other than it violates the conservation of energy. If there is a field in one permanent magnet and another in an equal magnet and there is repulsion, why can't we arrange a number of magnets to cause a indefinite rotation about an axis.

    Why does the law of conservation of energy only apply, there has to be an E&M law that also applies!
     
  13. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    shortbus, I think arrangement is a better way of describing the action. Is it a matter of correct arrangement that will cause/not cause continuous rotation?
     
  14. Kermit2

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    Feb 5, 2010
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    I was of the understanding that a magnet motor had been built, but it would only run very small loads, any attempt to get more than 50 watts work out of it resulted in a stalled rotor. The result of thousands of dollars of machining and building for a 'toy' motor.
    There is no way to control power in a magnet motor, no 'surge' current can flow to drive sudden heavy loads. The stall torque is apparently anything which resists the motor. Why bother?
     
  15. hgmjr

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    Jan 28, 2005
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    Aren't you conveniently ignoring the role played by friction in your permanent magnet motor which you correctly acknowledged would have brought to6afre's car to a halt.

    hgmjr
     
  16. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    Thanks, do you know the details of this motor, who built it? Design specs, etc? I am not looking for anything other than knowledge and that the proper arrangement of permanent magnets can cause continuous rotation.

    Thanks a lot.
     
  17. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    hgmjr, I'm not ignoring anything. I know friction plays a very important role. Thanks. I just want to make sure that isn't the only reason.
     
  18. AlexR

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    Jan 16, 2008
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    For an electric motor to turn you need a rotating magnetic field. The only way you are going to get that from a permanent magnet is if you physical spin the magnet, in other words use a motor to spin the magnet which will turn a motor which would all be pretty pointless.
     
  19. blueroomelectronics

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  20. cpu_user

    Thread Starter New Member

    Jan 16, 2011
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    AlexR, if you have two permanent magnets attached to two separate pivot points and such points separate the magnets and they oppose each other would there repulsion cause a rotating magnetic field?
    There has to be an E&M law that would dictate why they come to a stop due to its magnetic field interactions.
     
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