What type of motor can only operate from an AC power source?

Induction motors are designed specifically to operate using an alternating current (AC) power source. They work on the principle of electromagnetic induction, where electric current is induced in the rotor through the magnetic field created by the AC in the stator windings. This design enables efficient energy conversion and makes them widely used in various applications where steady speed and torque are required.

In contrast, DC motors operate solely on direct current and utilize different mechanisms to generate motion. Step motors, while capable of operating with both AC and DC power, depend heavily on positioning rather than continuous rotation, and servo motors involve a feedback system that can incorporate both AC and DC as well, depending on the motor's specifications. Therefore, induction motors stand out as the type explicitly designed to operate with AC power, confirming their unique role in AC systems.