FRIEDRICHSHAFEN, Germany—ZF has developed an electric motor that does not require magnets. The I2SM (In-Rotor Inductive-Excited Synchronous Motor) transmits energy for the magnetic field via an inductive exciter inside the rotor shaft. This makes the motor compact, with maximum power and torque density.

This advanced variant of a separately excited synchronous motor is an alternative to permanent-magnet synchronous machines (PSM). The latter are currently the motors most frequently used in electric vehicles, but they are based on magnets that require rare-earth materials for their production.