Brushed motorstatorbrushrotorarmature windingcommutatorarmature currentelectromagnetic torqueelectromagnetic interference

A pair of stationary main magnetic poles N and S with DC excitation are installed on the fixed part (stator) of the bipolar brushed DC motor, and an armature core is installed on the rotating part (rotor). There is an air gap between the stator and rotor. An armature coil connected by two conductors A and X is placed on the armature core, and the first and last ends of the coil are respectively connected to two arc-shaped copper plates, which are called commutator plates. The commutator segments are insulated from each other, and the whole composed of commutator segments is called a commutator. The commutator is fixed on the shaft, and the commutator segments are also insulated from the shaft. A pair of fixed electric brushes B1 and B2 are placed on the commutator, and when the armature rotates, the armature coil is connected to the external circuit through the commutator and the electric brushes.