If a motor hums but does not turn, what is likely the problem?

When a motor hums but does not turn, the situation typically indicates that the motor is receiving power but is unable to initiate movement. The humming sound arises from the motor's winding creating a magnetic field, which is typical in motors when they are energized.

Mechanical binding or phase loss is a likely cause in this circumstance. Mechanical binding occurs when components of the motor, such as bearings, gears, or the rotor itself, are obstructed or jammed, preventing rotation. This binding can create excess strain, resulting in the humming noise without any motion. Additionally, if a motor is a three-phase motor and experiences phase loss—where one of the three phases is interrupted—the motor may fail to turn because it requires all three phases to create a rotating magnetic field necessary for effective operation.

While the other options present possible motor issues, they do not specifically describe the humming without movement. For instance, a blown fuse would typically result in the motor not receiving power at all, causing silence rather than a hum. Incorrect voltage may not cause a hum; instead, it could lead to inefficiencies or immediate stalling without any sound. A defective motor could lead to a range of symptoms, but the distinct combination of humming and no rotation strongly points towards mechanical