A modular electromagnetic device has a stator and a rotor rotating between facing surfaces of the stator and bearing a plurality of magnets distributed with alternate orientations in a substantially ring-shaped pattern, and the stator comprises at least one pair of magnetic yokes symmetrically located at both sides of the rotor. Each yoke has a pair of projecting arms extending towards the magnets and bearing a respective coil for collection of electric power from or supply of electric power to the device. Each yoke is individually mounted on an own support equipped with adjusting units arranged to adjust the yoke position relative to the confronting magnets, and forms, together with its coils, its support, the adjusting units thereof, and sensing and control means controlling the yoke adjustment, an elementary stator cell that can be replicated to form single-phase or multiphase modules.