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Calculate the electromotive force E

  1. Dec 3, 2015 #1
    hi,
    How can I demonstrate the relationship of the electromotive force of a motor AC
    thank you
     

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  3. Dec 3, 2015 #2

    cnh1995

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    Motional emf will be induced in the rotor. Use E=BLVsinθ*N (where v=rw and N=number of turns of rotor).
     
  4. Dec 3, 2015 #3

    cnh1995

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    For detailed demo, you can first prove the motional emf equation using Lorentz's force(F=BILsinθ) applied on electrons of a conductor and then apply the emf equation to this alternator.
     
  5. Dec 3, 2015 #4
    which force you talk about ???
    the rectangle is fixed and the flow varies,
    I think to use the flow of magnetic induction,
    I think to use Faraday's relationship e = - dΦ / dt (the derivative currency flows on derivative temp).
    in using Φ=∫∫ B.dS
     
  6. Dec 3, 2015 #5

    cnh1995

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    Then you should use Faraday's laws.
    Right.
     
  7. Dec 3, 2015 #6
    but i find this expression : E = N L r w B cos(wt)
    ====> must find sin (wt) instead of cos (wt)
     
  8. Dec 3, 2015 #7

    cnh1995

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    Then you should assume the varying flux as a cosine wave.
    sin(wt)=cos(π/2-wt).
     
  9. Dec 5, 2015 #8
    i have cos(wt) not sin(wt) !!
     
  10. Dec 5, 2015 #9

    cnh1995

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    Your varying flux function should be predefined, either sin or cos. If it is sin, emf will be in cos(wt).
     
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