What determines the rotation of a single phase motor?

The rotation of a single-phase motor is determined by the direction of current through the start winding. Single-phase motors rely on the principle of creating a rotating magnetic field to produce torque, and this is achieved through the interaction of the start winding and the main winding. When current flows through the start winding, it creates a magnetic field that interacts with the magnetic field from the main winding, determining the direction of the motor's rotation.

The start winding is designed to phase-shift the current, which helps in establishing the initial starting torque. Therefore, altering the direction of the current in the start winding will change the direction of the magnetic field produced, effectively reversing the motor's rotation. Understanding this foundational concept is critical for anyone working with single-phase motors, as it directly relates to their operation and control.

Factors such as the motor's design, the voltage supply, or the type of capacitor may influence performance, efficiency, or starting capability, but they do not fundamentally determine the rotational direction as the start winding does.