Brushed DC in practical applications
In practical applications, the main magnetic pole may be a permanent magnet or an electromagnet. Generally, large motors use electromagnets for the main magnetic poles and permanent magnets for small motors.
Brushless DC motor
In brushed DC motors, the brushes and commutator segments are always in a frictional state and are fragile components. In order to avoid the presence of such components, brushless DC motors are on the scene.
Brushless DC motor working principle
The stator is the winding and placed in the outer ring; the rotor is a permanent magnet placed in the center. The stator is subjected to a controlled square wave current, and the direction of the excited magnetic field changes with the direction of the excitation current. The permanent magnet rotor is subjected to a torque in the transformed magnetic field, and then rotates.
In this way, the brush and the commutator are naturally eliminated without the need to energize the rotating parts.
