Composed of a set of contact rods fixed on the rotating shaft of the machine, and connected to the armature winding is the commutator; when the shaft rotates, the commutator will reverse the flow of current in the winding, for a single electric Pivot winding, when the shaft has completed a semi-complete turn, the windings are now connected so that the current flows through it in the opposite direction to the original.
At least three contact pieces are required to form a simple commutator to prevent the commutator from "dead". The two-brush simultaneous bridge has only two commutator pieces. The brush is wider than the insulation gap, ensuring that the brush is always in contact with the armature coil. The commutator has at least three segments. Although the rotor may stop in one position and two commutator segments touch one brush, this weapon with only one rotor will still be correct. With the remaining rotating arms, the motor can generate enough torque, the rotor starts to rotate, and the generator can provide power to the external circuit.
The commutator is relatively inefficient and requires regular maintenance, such as bristles replacement. Therefore, the transfer machines are decreasing in use and are replaced by alternating current (AC) machines. In recent years, the brushless DC motors used in pipe switches are used in pipe switches. A switch was used.
In a motor, the armature current causes a fixed magnetic field to generate a rotational force, or rotates on the coil to make it rotate; in a generator, the mechanical torque applied to the shaft maintains the armature winding through the fixed magnetic field, thereby in the coil Generate current. In the case of a motor and a generator, the commutator periodically reverses the current flow through the coil, so that the current flow outside the circuit only continues in one direction.