an electromechanical transducer has a coreless rotor or stator winding formed of a series of flat band loops , in case of a long or short cup - shaped cylindrical winding , each of the loops having an active portion inclined to both the axial and tangential direction of the rotor or stator winding and an inactive bowstring portion oriented perpendicular to the axial direction thereof . in case of a nearly flat disc or dish shaped rotor or stator winding , each of the loops has a main active portion at a top or bottom portion of the winding , the active portion being perpendicular to the axial direction of the winding . an output torque to be generated therefrom an effective magnetic flux area and density is improved .