A DC motor [1] is an electric motor that converts direct current electrical energy into mechanical energy. Due to its excellent speed regulation performance, it is widely used in power transmission. DC motors are classified into three types based on the excitation method: permanent magnet, external excitation, and self-excitation. Among them, self-excitation is further divided into parallel excitation, series excitation, and compound excitation.
When a direct current power supply supplies current to the armature winding through the brush, the conductors under the N pole of the armature surface can flow in the same direction, and according to the left-hand rule, the conductors will be subjected to a counterclockwise torque; the conductors under the S pole of the armature surface also flow in the same direction, and according to the left-hand rule, the conductors will also be subjected to a counterclockwise torque. Thus, the entire armature winding (rotor) will rotate counterclockwise, and the input direct current energy will be converted into mechanical energy output on the rotor shaft. The stator and rotor are composed of: base, main magnetic pole, commutating pole, brush device, etc.; the rotor (armature): armature core, armature winding, commutator, rotor shaft and fan, etc.