Please I need your help with DC motor circuit

Discussion in 'Homework Help' started by liutukas0725, Nov 21, 2012.

  1. liutukas0725

    Thread Starter New Member

    Nov 21, 2012
    2
    0
    Hi Lady s and Gentlemen,

    I am struggling with one of the question from coursework sheets, could you help me please?
    A permanent magnet DC motor has an armature resistance of 0.5  and when a voltage of 120 V is applied o the motor it reaches a steady-state speed of rotation of 20 rev/s and draws 40 A. What will be (a) the power loss in the armature and (b) the power input to the motor?

    Hopefully some one will give me a clue. I am not sure if the current given is the armature current or the real current of motor.

    Many thanks
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
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    It depends, what motor model are you using?

    This may be of assistance...
     
  3. liutukas0725

    Thread Starter New Member

    Nov 21, 2012
    2
    0
    Well it does not say in the question...might it be the problem for solving it?
     
  4. kris.92

    New Member

    Nov 26, 2012
    11
    1
    the kind of motor doesnt matter if it says its a permanent magnet motor. (that is the motor). You have all the information in the question to answer it. I don't want to give you the answer, but just dont get caught up in the model of motor nonsense.
     
    #12 likes this.
  5. tshuck

    Well-Known Member

    Oct 18, 2012
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    Really? What equations do you apply then? This is highly dependent of the motor model used. A simple series resistance can be used, or a whole 2nd order system. The solution depends on the model.
     
  6. #12

    Expert

    Nov 30, 2010
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    Think: What windings does a permanent magnet motor have besides the armature winding?
     
  7. tshuck

    Well-Known Member

    Oct 18, 2012
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    You are asking me?
     
  8. #12

    Expert

    Nov 30, 2010
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    No. I am replying to the original poster.
     
  9. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
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