What is the function of the starting winding in a split-phase motor?

The function of the starting winding in a split-phase motor is to provide an initial phase shift for startup. When a split-phase motor is powered, the starting winding and the run winding are energized, creating two magnetic fields that are out of phase with each other. This phase difference generates a rotating magnetic field, which is crucial for starting the motor. Once the motor reaches a certain speed, a centrifugal switch or relay disconnects the starting winding from the circuit, allowing the motor to run on the run winding alone.

This initial phase shift is essential because it enables the motor to overcome inertia and start turning. The design of the starting and run windings ensures that the motor has adequate torque to start and accelerate to its operational speed. In contrast, the other functions mentioned in the options do not align with the purpose of the starting winding. For instance, it does not provide constant power, enhance efficiency of the run winding, or create a short circuit upon failure. Each of these functions would be unrelated to the specific role of the starting winding within a split-phase motor.