Does a three phase motor require a start winding?

A three-phase motor generally does not require a start winding. The design of three-phase motors allows them to produce a rotating magnetic field that is sufficient to start the motor without the need for additional components like a start winding, which is commonly found in single-phase motors.

In three-phase systems, the balanced three-phase supply provides the necessary torque to begin rotation as soon as power is applied. This inherent design advantage means that three-phase motors are often more efficient and reliable for continuous operation compared to their single-phase counterparts.

The other options suggest scenarios that do not align with the operational characteristics of three-phase motors. For instance, suggesting that a three-phase motor always requires a start winding implies a misunderstanding of its fundamental operation, while the idea of it being optional in all situations overlooks the standard designs employed across various types of three-phase motors. Additionally, stating that only high torque applications require a start winding overlooks the general principle that three-phase motors inherently do not need them at all.