I'm somewhat confused by the top attached torque vs. speed curve for a vfd operating a motor below base speed. Can someone explain to me why the maximum torque decreases for speeds below base speed. I was under the assumption that as long as you kept the V/Hz ratio constant below base speed then you would have the maximum torque avaliable for the motor throughout the entire speed range. Why does this plot appear to be showing the torque decreasing with speed?
I understand that the bottom plot shows torque for speeds above base speed and that it shows a reduced torque values above base speed since the voltage is fixed. This reduced torque above base speed makes sense to me, however I cant seem to justify the top curve for speeds below base speed.
Can someone help explain?
I understand that the bottom plot shows torque for speeds above base speed and that it shows a reduced torque values above base speed since the voltage is fixed. This reduced torque above base speed makes sense to me, however I cant seem to justify the top curve for speeds below base speed.
Can someone help explain?