A brush DC motor is a rotating electrical machine that converts DC electrical energy into mechanical energy or converts mechanical energy into DC power through a built-in brush arrangement. It can change the running speed by changing the working voltage or magnetic field strength.
The basic structural components of a brush DC motor include the stator, rotor, brushes, and commutator. The stator and rotor magnetic fields interact to drive the motor to rotate. Furthermore, stator windings and rotor windings can be connected in parallel, series or mixed. These three types of brush DC motors are called parallel motors, series motors and double excitation motors.
A brush DC motor has a rotor with coils that are surrounded by magnets in the stator. Both ends of the coil are connected to a commutator, which in turn is connected to brushes so that direct current can pass through the brushes and coil. When the coil rotates, the misalignment of the brush and commutator prevents the current from passing, but it continues to rotate, so that the brush and commutator re-contact, and the current continues to flow. This repeated switching of current allows the brush DC motor to continue spinning.
Brush DC motors have features with cost-effective, easy to use, and provide outstanding performance. But since the brushes and commutator are in constant contact as the motor spins, noise is generated. After a long period of use, it will result in the brushes gradually wear out, and the motor will stop working in the long run. Therefore, it is necessary to check or replace the brushes regularly for maintenance.