Which of the following is a feature of split-phase motors?

The characteristic that defines split-phase motors is their design which includes two separate windings that create two different magnetic field phases. These windings are often referred to as the starting winding and the running winding. The phase difference between the two currents flowing in these windings is what enables the motor to start and operate effectively.

This feature allows the motor to leverage a phase shift to create the necessary starting torque, making it an essential aspect of the motor’s functionality. The winding arrangement helps in generating the necessary starting torque without the need for additional components like capacitors or complex control systems.

As for the other choices, while split-phase motors do operate on AC current, not all motors have the same AC operational profile. Some options refer to features typically associated with other types of motors, such as variable speed control or the use of start capacitors, which are not necessary for the operational functionality of a typical split-phase motor. Thus, the correct focus is on the phase distinction enabled by the two windings, affirming the correctness of the answer.