Indeed, 3-phase AC induction motors are such an engineering marvel, simple, cheap, rugged, high efficiency. They are used by e.g. Tesla and in locomotives. Tha

Indeed, 3-phase AC induction motors are such an engineering marvel, simple, cheap, rugged, high efficiency. They are used by e.g. Tesla and in locomotives. That being said, IIRC PM motors do have some (minor) advantages, particularly for small motors.