Which of the following is not a function of motor control?

The correct answer is that "none of the above" refers to the fact that all listed functions—starting the motor, stopping the motor, and changing the motor's direction—are indeed essential functions of motor control. Motor control systems are designed to manage the operation of electric motors through a variety of control mechanisms.

Starting the motor is crucial as it initiates the operation, allowing the motor to reach its required speed and performance level. Stopping the motor is equally important for safety and operational control, allowing for the safe shutdown of the motor when necessary. Changing the motor's direction is significantly relevant in many applications, such as in robotic systems or conveyor belts, where direction reversibility is essential for proper functioning.

Therefore, since all the provided options are vital functions of motor control systems, selecting "none of the above" accurately indicates that there are no functions listed that fall outside the scope of motor control.