(1) In the commutator motor, the brush also plays a commutation function, which can change the direction of current;
(2) The grounded carbon brush can output current and introduce the static charge on the main shaft to the ground through the carbon brush;
(3) The external current (excitation current) is added to the rotating rotor through the carbon brush (input current) the motor carbon brush;
(4) Lead the large shaft (ground) to the protection device for grounding protection of the rotor and measuring the positive and negative of the rotor. The ground voltage commutator is composed of a brush and a commutating ring. The carbon brush is a kind of brush.