To provide a motor that is suitable as a series-wound DC motor for usage where large starting torque is required, in which no expensive permanent magnet is used, and no maintenance of which is required with a brushless structure.

The large starting torque is achieved by performing both the excitation of an electric magnet as replacement for the permanent magnet and power supply to an armature, in series at both front and rear of one inverter, and the brushless structure is attained by structuring a rotor which does not have windings.