a single phase , rotary electromagnetic actuator comprising first and second stator assemblies , located in oppositely facing spaced apart positions along a common central axis , permits a magnetized disc magnet rotor to rotate about the common axis free of any magnetic attractive forces normally tending to move the disc magnet longitudinally along the axis , or alternatively to be located in a position to create a desired longitudinal attractive force . the entire assembly is maintained in operative positions by a circular belt which provides an inward facing lip on each side of which the stator assemblies are seated and which determines the magnetic airgap spacing for the disc . the invention may be implemented as a servo - actuator by the inclusion of an angular position sensor that uses the actuator rotor as the magnetic field emitter , and a receiver for the magnetic field and its contacts , located in the belt lip .