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How to design a single phase induction motor

  1. May 21, 2015 #1
    Hi everyone....
    I have to design a single phase induction motor.
    I have some questions and it would be great if you could help me. The parameters I have for the design of the motor are: rated power, rated voltage, frequency, rated speed, power factor, efficiency, full load current and full load torque.
    I need some information of how to calculate other parameters, such as flux density, core length, air gap, size of both stator and rotor and their slots etc. I have found some equations for calculating all these for a 3 phase induction motor and I wonder if I can use them for the singe phase induction motor too.
    I really appreciate your help , thank you very much!
  2. jcsd
  3. May 21, 2015 #2


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    I don't know as I have not seen your equations.

    As for a single phase motor you need only one (primary) winding. The motor can run, but it cannot start because it does not know in which direction to start. ( You can only induce a magnetic field in one dimension, which leaves no "space" to create angles ).

    Therefore you must have an extra "starting coil" that has an electrical angle of say 90° as to the primary winding. This angle is provided by connecting a capacitor in series with the starting coil, thereby making a current phase shift in the starting coil and a "second dimension". So the coils in the single phase motor are not symmetrical as in the 3 phase motor, and thus (some of) the equations for the 3 phase motor cannot be used by the single phase motor.

    This is very hard to explain in short.
  4. May 21, 2015 #3
    How could i find these equations refering to the single-phase motor? Is there any paper or something?
  5. May 24, 2015 #4

    jim hardy

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