Abstract: A motor including a rotor member having a symmetric shape relative to a shaft to which the rotor member is being fixed. An annular magnet assembly is fixed to the rotor member with the shaft passed therethrough at a center thereof. The magnet assembly is provided with an even number of driving magnetized elements of north and south poles alternatively aligned at a perimeter of the magnet assembly. First sensed magnetized elements are provided in the driving magnetized elements in an opposite pole relation with the corresponding driving magnetized element, and second sensed magnetized elements provided in two adjacent ones of the driving magnetized elements in an opposite pole relation with the corresponding driving magnetized element. The motor further includes a magnetic field sensor assembly opposed to the magnet assembly for sensing alternating magnetic fields as the rotor member rotates.