A wound-rotor induction motor with external resistance is classified as what type of motor?

A wound-rotor induction motor with external resistance is classified as a multispeed motor due to its ability to operate at different speeds. By varying the external resistance connected to the rotor circuit, the slip of the motor can be controlled, allowing for changes in the speed of the motor under different loads. This feature makes wound-rotor induction motors versatile for applications requiring different operational speeds, such as in cranes, mills, and conveyors.

In contrast, a constant-speed motor maintains a fixed speed regardless of load variations, which does not apply to wound-rotor induction motors equipped with external resistance. Similarly, a single-speed motor operates at one designated speed, which again does not describe the variability possible with this type of motor. Lastly, while wound-rotor induction motors can indeed provide high starting torque due to the external resistance, this characteristic alone does not define them as high-torque motors, since torque performance can vary significantly under different conditions. Thus, the designation as a multispeed motor accurately reflects its functional capabilities.