Rotatable single-phase electromagnetic actuator

Single-phase constant torque electromagnetic actuator, comprising:

• a coupling shaft having a longitudinal axis;
• a bore shaped movable device having a longitudinal axis and a flat annular surface, the movable device rigidly attached to the coupling shaft such that the longitudinal axis of the coupling shaft is aligned with the longitudinal axis of the movable device;
• an annular magnetic disk fixed on the flat annular surface of the movable device, the magnetic disk having poles magnetized in alternating axial directions;
• a stationary device including a stator circuit made of a high-permeability magnetic material and a trip coil for exciting the stator circuit, the stator circuit cylindrically shaped and having an outer diameter equal to an outer diameter of the magnetic disk, wherein the stationary device remains stationary with respect to the movable device;
• a thrust ball bearing including an annular ball race and ball bearings positioned within the ball race, the thrust ball bearing fixed to the stationary device, the ball race having an outer diameter equal to an inner diameter of the magnetic disk;
• wherein the movable device is detachably engaged in close proximity with the stationary device such that a uniform space is formed at every point between the magnetic disk and the stationary device, thereby magnetically coupling the magnetic disk to the stator circuit, the outer diameter and the inner diameter of the magnetic disk aligned with the outer diameter and an inner diameter of the stator circuit, respectively, the movable device rotatable about a rotational axis with respect to the stationary device,
• wherein the movable device cannot move in a lateral direction to the stationary device, but is free to tilt at an offset to the rotational axis;
• a lever formed by a portion of the movable device disengaged from the ball bearings by the offset to the rotational axis;
• and
• a fulcrum formed by some of said ball bearings engaged with the movable device when the rotational axis is offset,
• wherein a magnetic force generated by magnetic coupling of the magnetic disk to the stator circuit acts upon the lever and the fulcrum in a direction which corrects the offset of the rotational axis.