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??

 

Hi. Can someone explain to me more about the constant power region of an induction motor.

Constant power means that output torque times the angular speed is staying the same.

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??

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.

 

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.

 

This might be useful as background reading ..... includes a brief section on different load types, including constant power.

http://ww1.microchip.com/downloads/en/AppNotes/00887a.pdf