Induction motor

Discussion in 'Homework Help' started by Cerkit, May 11, 2010.

  1. Cerkit

    Thread Starter Senior Member

    Jan 4, 2009
    Hi. Can someone explain to me more about the constant power region of an induction motor. In this region does it mean that the torque is dynamic depending on how the load changes but that the power supplied to the motor will remain constant??
  2. steveb

    Senior Member

    Jul 3, 2008
    Constant power means that output torque times the angular speed is staying the same.
    I think yes, - at least approximately (and maybe not in all cases).

    Constant output power happens if the motor is under a closed loop vector control that deliberately maintains constant power (speed and dq- rotating frame currents are measured and used with feedback). Or, (in the open loop case) there can be operating regions where efficiency is nearly constant and constant input electrical power translates to constant mechanical output power.
    Last edited: May 11, 2010
  3. retched

    AAC Fanatic!

    Dec 5, 2009
    If you think of it like operating an automobile, While you are taking off from a stop, you feel the pull of the acceleration. Keeping the tach at 3000 rpm the entire time, eventually you will reach a speed where the 3000 rpms are not producing any acceleration. The motor still has potential torque when the load requires it, like reaching a hill. The power region is the area where the torque is still being applied to the load at a given input power, not just keeping it going.

    So the power region ends when applied torque decreases when input power stays the same.
  4. t_n_k

    AAC Fanatic!

    Mar 6, 2009