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DC motor rotor + stator : torque by attraction ?

  1. Jun 6, 2012 #1
    DC motor rotor + stator : torque by attraction ? [Solved]

    So on that image there's a very simple dc motor.

    Knowing that F = B*I, the force acting on the wire can be represented as on the image.
    Also the current passing through the rotor will create a magnetic field, represented by Brotor, pointing downards.
    Acording to the first image, it will rotate as if the magnetic fields align, because of the F = BI equation, so both magnetic fields would point in the same direction.

    TlaMt.gif


    On the other hand, here we just have that the opposite poles attract, so the force is for the magnetic fields to point in opposite directions.

    Uaml2.jpg

    I'm having some difficulty understanding this, because these concepts seem to contradict each other.

    1Plpe.png

    So where am i thinking wrong here?
     
    Last edited: Jun 6, 2012
  2. jcsd
  3. Jun 6, 2012 #2
  4. Jun 6, 2012 #3
    Ok i think i've come to grips to what's causing the confusion.

    Since i saw the magnet flux from north to south, i assumed wrongly that South is where the flux vector always points.

    But it seems it only points in the direction of the flux on that specific location. So both images are correct and this problem is solved.

    magpart3a.gif
     
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