Three ways to make a motor magnetic
Permanent magnets, induction and electrical excitation create a rotor’s magnetic field in different ways, with different engineering compromises.
Canvas of Knowledge · 14 November 2026 · Illustrated explainerPermanent magnets
A permanent-magnet rotor carries its magnetic field with it. Material choices, cooling and rotor strength influence efficiency and the speed the machine can sustain.
Two alternatives
An induction motor creates rotor currents electromagnetically. An electrically excited synchronous motor supplies current to rotor windings. Neither principle needs permanent magnets in its rotor.
Real-world choices
Xiaomi highlights rotor materials and cooling in its HyperEngine motors. BMW describes electrically excited rear motors and asynchronous front motors for its Gen6 all-wheel-drive architecture.
THE IDEA TO KEEPThere is no universal best motor: the answer depends on the duty cycle, materials, packaging and control strategy.
Sources & further reading
Sources reviewed 14 November 2026. Specifications and availability depend on the product, market and date. Source organisations do not endorse this website.