Working principle of brush DC motor

There are magnets in the fixed part of the brushed DC motor, here called the main magnetic pole; there are also brushes in the fixed part. The rotating part has an annular iron core and windings wound around the annular iron core.

A pair of stationary main magnetic poles N and S of DC excitation are installed on the fixed part (stator) of the two-pole brushed DC motor, and an armature core is installed on the rotating part (rotor). There is an air gap between the stator and the rotor. An armature coil is placed on the armature core, which is connected by two conductors A and X. The head and end of the coil are respectively connected to two arc-shaped copper sheets, which are called commutation segments. The commutator segments are insulated from each other, and the whole composed of the commutator segments is called a commutator. The commutator is fixed on the rotating shaft, and the commutator piece and the rotating shaft are also insulated from each other. A pair of stationary brushes are placed on the commutator segment. When the armature rotates, the armature coil is connected to the external circuit through the commutator segment and the brushes.