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Homework Help: Asynchronous motor question

  1. Jun 2, 2013 #1
    1. The problem statement, all variables and given/known data
    number of pole pairs p =2
    line frequency f=50hz
    number of rotations n=1250 1/min

    2. Relevant equations

    3. The attempt at a solution

    question is number of rotations of the rotary magnetic field (1/min units)
    the slip of the machine(s)
    the frequency of the rotor current ?

    please help me to solve this kind of problems i have like 5 more questions which is smilar to this one so i can learn how to solve others thank you from now good luck at your exams :)
  2. jcsd
  3. Jun 2, 2013 #2


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    Homework Helper

    If you have the line frequency and the number of pole pairs, you can get the rotation of the stator Ns by using

    [tex]N_s = \frac{120f}{p}[/tex]

    where f is the line frequency and p is the number of poles.

    How is slip defined?
  4. Jun 2, 2013 #3
    s = Ns-Nr/Ns Ns is stator electrical speed, and Nr is rotor mechanical speed. thank you for your helps sir.
  5. Jun 2, 2013 #4


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    Homework Helper

    Right, so using the formula I gave you above, you can get Ns. They gave you the value of Nr, so can you get the slip?
  6. Jun 2, 2013 #5
    yes sir your help was enough, i wish you best of luck and thank you so much.
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