Abstract: The invention contemplates a rotary valve which uses a brushless DC-motor to directly drive the flow control member of the valve. The motor is of toroidal-torque variety, with a wound stator that is fixed to the valve body, and a rotor which is fixed to the valve member. In a first embodiment, one polarity of transient stator excitation drives the rotor in one direction, from one to the other magnetically latched end of a limited angular excursion, and the opposite polarity of transient stator excitation drives the rotor in the opposite direction, to reverse the magnetically latched condition of the rotor and, therefore, of the valve member. In a second embodiment, a torsion spring is connected to apply torque in opposition to rotor displacement from one of the limits of its angular excursion, and the extent to which the valve member is operated is a function of the instantaneous magnitude of stator excitation.