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Moving magnetized objects apart

  1. May 3, 2016 #1
    I want to move a steel object/plate away from a magnet - Here is my questions:

    1. Can I induce an electrical current to a steel plate just large enough to allow me to pull the plate away without much attraction to a magnet? So I guess it would kind of being like the reverse of turning on an electromagnet?

    2. If this can be done...will it result in some kind of permanent reduction of magnetism for the steel plate if done repeatedly?
  2. jcsd
  3. May 3, 2016 #2

    Paul Colby

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    I'm not certain what you are trying to do. Have you looked at magnetic chucks? They are devices that use variable air gaps to reduce the clamping between the chuck and the part being held.

    For 1) the answer is yes. Just coil windings about the magnet and drive a current sufficient to null or reduce the field.
    For 2) I think this depends on the B-H hysteresis curve of the magnetic material and how far along this curve the induced field goes.
  4. May 3, 2016 #3
    I am just trying to imagine a way for magnets to do work on an object -- hoping to maybe patent something but I am not very well versed on the deep workings of how magnets work.

    -- in response to your answer # 1 -- I don't want to neutralize the magnet but the steel plate that is attracted to --- I am assuming yes?

    -- in response to # 2 -- does the B-H hysteresis factor a function of how large the electric current is that is used to reduce the magnetism of the plate?
  5. May 3, 2016 #4

    Paul Colby

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    Magnets do work on objects through a number of ways. There is the ##dW=F\cdot ds## mechanical work. Then there is the energy term ##\int{B\cdot H dx^3}## which is the energy stored in the magnetic field. Typically ##H(B)## is a multi-valued function so as ##B## is changed work is done heating the object in proportion to the area enclosed in the ##B##-##H## curve. If you are trying to get help on something you feel is proprietary best of luck. I likely can't help.
  6. May 4, 2016 #5


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    What exactly are you trying to do? You can't make energy by somehow turning a permanent magnet on and off. It doesn't mater if you try to use coil or some sort of moving shield to turn off the magnet.
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