In a motor-driven power steering apparatus, the main coil winding and
auxiliary coil winding are wound around the same slot of a stator core in
a parallel manner, a motor drive means has a main driver feeding at least
to the main coil windings, and an auxiliary driver feeding only to the
auxiliary coil windings, the main driver being actuated so as to be
capable of assisting the steering during normal conditions of a control
system of an electric motor, and the auxiliary driver is actuated so as
to execute an auxiliary assist corresponding to a motor friction torque
under abnormal conditions of the control system of the electric motor.