A DC motor is an electric motor that converts direct current electrical energy into mechanical energy. Due to its excellent speed-control characteristics, it is widely utilized in electric drive systems. Based on their excitation methods, DC motors are classified into three categories: permanent magnet, separately excited, and self-excited. The self-excited category is further subdivided into three types: shunt, series, and compound.
When a DC power source supplies current to the armature winding via the brushes, conductors situated beneath the stator's North (N) pole carry current flowing in a uniform direction; according to the left-hand rule, these conductors experience a counter-clockwise torque. Similarly, conductors located beneath the stator's South (S) pole also carry current flowing in the same direction and, by the same left-hand rule, are likewise subjected to a counter-clockwise torque. Consequently, the entire armature winding-that is, the rotor-rotates in a counter-clockwise direction, thereby converting the input DC electrical energy into mechanical energy output at the rotor shaft. The motor consists of two primary components: a stator and a rotor. The stator comprises the base, main magnetic poles, interpoles, brush assembly, and other elements; the rotor (armature) consists of the armature core, armature winding, commutator, rotating shaft, cooling fan, and related parts.
