MOTOR AND METHOD OF CONTROLLING IT

摘要

The motor unit comprises a stator, two independent rotors having each a permanent magnet located in a cylindrical space defined by three pole faces of the stator, two windings and at least a positioning magnet for holding both rotors, in the absence of current in the windings, in a position in which the magnetic axes of their magnets are each coincident with a rest axis. The field produced by the flow of a current in one of the windings is always at an obtuse angle to one of the rest axes and at an acute angle to the other. The two rotors perform steps of 360 DEG independently of each other in response to pairs of current pulses, the first of which is applied to one of the windings and the second of which is applied to the other winding. The direction of the current pulses determines which of the rotors performs a step, and the order in which the current pulses are applied to the windings determines the direction of rotation of that rotor. The motor unit can be used in particular in an electronic timepiece.