What is commonly used to enhance the starting torque of single-phase motors?

Single-phase motors often lack sufficient starting torque for certain applications, making it necessary to enhance their starting capabilities. A capacitor is commonly used for this purpose. When a capacitor is added to the motor circuit, it creates a phase shift in the current, which helps establish a rotating magnetic field. This rotating magnetic field generates a torque that aids the motor in starting up, providing the necessary initial push.

The use of a capacitor allows for better performance of the motor at startup, enabling it to overcome inertia and begin spinning efficiently. Various types of single-phase motors, such as capacitor-start motors and permanent split capacitor motors, explicitly rely on capacitors to achieve higher starting torque compared to motors that do not incorporate this component. This enhancement is essential in applications that require immediate activation or where the load has a significant inertial resistance.

While rheostats, inductors, and transformers serve important roles in electrical circuits and motor functions, they do not directly contribute to increasing the starting torque in single-phase motors in the same effective manner as capacitors.