Prior to the advent of the adjustable-speed drive (ASD), the polyphase induction motor operated as a constant-speed motor. Figure 1 shows the well-known torque and current curves versus speed for the ...

A synchronous and synchronous motors are the two main categories of ac motors. The induction motor is a common form of asynchronous motor and is basically an ac transformer with a rotating secondary.

Matching drive to motor is essential to gain the best combination of torque, speed, and efficiency. Selecting the right drive is essential to getting the best performance and efficiency from an ...