A rotary electromagnetic actuator comprising: two active stators of a high permeability ferromagnetic structure, each of said active stators having a U-shaped cross section in a plane extending along an axis of said actuator, each stator having two poles, each pole being adapted to receive an excitation coil winding to produce a magnetic flux, each stator having a base extending between 2 stator poles thereof, each stator having a structure with two stator poles having two opposed inner parallel flat surfaces extending to a base, each stator pole being of the same shape and size, each stator pole having an end face, each stator pole having two slanted side surfaces extending from the flat surface on both sides with the same angle, and the two stators being axially spaced apart a predetermined distance defining an airgap dimension E, a height H of each stator pole above the base being less than eight times the air gap E, wherein the two stator poles of each of the active stators are spaced apart a radial distance D separating said two opposed inner parallel flat surfaces along a direction perpendicular to said parallel flat surfaces, such that the ratio of D to E is in a range of 4 to 5; an inertia assembly comprising: a shaft defining the axis of the actuator; a disc magnet rotor absent a yoke of high permeability magnetic material mounted on the shaft for rotating the shaft, the rotor magnet being axially magnetized with 2 pole pairs of alternating polarity; the rotor being in the air gap E and spaced from each stator by a predetermined distance; whereby a closed-loop magnetic flux circuit flows from the first pole of the first active stator, then through the first pole pair of the rotor, then through the first pole of the second active stator then through the base of the second stator, then through a second pole thereof, and then through the second pole pair of the rotor, then through the second pole of the first active stator, then through the base thereof and then returning to the first pole of the first active stator, and the interaction between the rotor's magnetic field and the stators' magnetic field will result in the generation of a torque delivered to the shaft. two active stators of a high permeability ferromagnetic structure, each of said active stators having a U-shaped cross section in a plane extending along an axis of said actuator, each stator having two poles, each pole being adapted to receive an excitation coil winding to produce a magnetic flux, each stator having a base extending between 2 stator poles thereof, each stator having a structure with two stator poles having two opposed inner parallel flat surfaces extending to a base, each stator pole being of the same shape and size, each stator pole having an end face, each stator pole having two slanted side surfaces extending from the flat surface on both sides with the same angle, and the two stators being axially spaced apart a predetermined distance defining an airgap dimension E, a height H of each stator pole above the base being less than eight times the air gap E, wherein the two stator poles of each of the active stators are spaced apart a radial distance D separating said two opposed inner parallel flat surfaces along a direction perpendicular to said parallel flat surfaces, such that the ratio of D to E is in a range of 4 to 5; an inertia assembly comprising: a shaft defining the axis of the actuator; a disc magnet rotor absent a yoke of high permeability magnetic material mounted on the shaft for rotating the shaft, the rotor magnet being axially magnetized with 2 pole pairs of alternating polarity; the rotor being in the air gap E and spaced from each stator by a predetermined distance; a shaft defining the axis of the actuator; a disc magnet rotor absent a yoke of high permeability magnetic material mounted on the shaft for rotating the shaft, the rotor magnet being axially magnetized with 2 pole pairs of alternating polarity; the rotor being in the air gap E and spaced from each stator by a predetermined distance; whereby a closed-loop magnetic flux circuit flows from the first pole of the first active stator, then through the first pole pair of the rotor, then through the first pole of the second active stator then through the base of the second stator, then through a second pole thereof, and then through the second pole pair of the rotor, then through the second pole of the first active stator, then through the base thereof and then returning to the first pole of the first active stator, and the interaction between the rotor's magnetic field and the stators' magnetic field will result in the generation of a torque delivered to the shaft.