What distinguishes wound rotor induction motors from standard induction motors?

Wound rotor induction motors are distinguished by their ability to control speed more effectively compared to standard induction motors. This ability is largely due to the rotor construction, which uses windings instead of a squirrel-cage rotor. In a wound rotor motor, external resistors can be connected to the rotor windings through slip rings, allowing for greater control over the rotor's electrical characteristics.

By varying the resistance in the rotor circuit, operators can adjust the slip, which allows for finer control over speed. This capability is particularly beneficial in applications requiring a wide speed range or varying load conditions. As the speed can be adjusted more responsively, it makes wound rotor induction motors ideal for situations needing precise speed regulation.

While other options such as higher efficiency at low speeds, increased torque at startup, and lower maintenance requirements might be features associated with different types of motors, they do not specifically encapsulate the unique operational advantage that wound rotor induction motors offer through effective speed control.