Video narration
How can a permanent-magnet rotor follow a rotating field without slipping? Think of a compass needle turning toward a nearby rotating magnet. A Permanent Magnet Synchronous Motor, or PMSM, uses that idea: three-phase stator currents create a rotating magnetic field, and the permanent-magnet rotor locks to it. Synchronous speed follows electrical frequency and pole count: n_s equals 120 f divided by P in rpm, where P is the number of poles. So steady-state speed has no slip. Here's the key shift: frequency sets speed; controlled current and magnetic angle set torque. Torque can stay high at fixed speed. Below base speed, the drive holds approximately constant torque. Above it, rising back-EMF consumes the available voltage. Field weakening reduces air-gap flux, so torque falls while power stays constant. So yes: the rotor follows the field without slipping; frequency sets speed, current sets torque, and voltage limits high-speed torque.