Permanent-Magnet Motor
Permanent-magnet motor (PM motor) is an electric motor that uses permanent magnets to provide all or part of its magnetic field.
What the name covers
In an EV traction motor, the magnets are usually on or inside the rotor while controlled stator current produces torque. The label does not by itself identify the motor's exact geometry, commutation method, magnet material, or contribution from reluctance torque. A Permanent-Magnet Synchronous Motor (PMSM) is the most common automotive interpretation, but “permanent-magnet motor” remains the broader family name.
Permanent magnets avoid continuous electrical excitation of the rotor, supporting compact and efficient designs. They also create material, temperature, high-speed retention, and field-weakening constraints. “Permanent magnet” does not necessarily mean “rare earth”: ferrite and other magnet materials are possible, although many high-power-density traction motors use rare-earth magnets.
For the detailed motor and control principles, see Permanent-Magnet Synchronous Motors.