What causes a rotor to rotate in a motor?

What causes a rotor to rotate in a motor?

• A. The rotor's own magnets
• B. The ambient temperature
• C. The rotor being physically rotated
• D. The magnetic field rotating from the stator

Answer: (D)

A motor turns because a magnetic field moves relative to the rotor, creating torque. When the stator windings are fed with alternating current, they produce a magnetic field that appears to rotate around the stator. This moving field interacts with the rotor—either by inducing currents in a conductive rotor or by pulling on rotor magnets—producing a continuous torque that makes the rotor spin. The other ideas don’t drive rotation: the rotor’s own magnets don’t create motion by themselves, ambient temperature doesn’t generate torque, and rotating the rotor by hand is external input, not the motor’s mechanism.

A motor turns because a magnetic field moves relative to the rotor, creating torque. When the stator windings are fed with alternating current, they produce a magnetic field that appears to rotate around the stator. This moving field interacts with the rotor—either by inducing currents in a conductive rotor or by pulling on rotor magnets—producing a continuous torque that makes the rotor spin. The other ideas don’t drive rotation: the rotor’s own magnets don’t create motion by themselves, ambient temperature doesn’t generate torque, and rotating the rotor by hand is external input, not the motor’s mechanism.