The difference between brushless and brushed industrial large fan permanent magnet motor

After more than a decade of development, industrial ceiling fans have expanded from traditional deceleration motor fans to include permanent magnet motor fans to match the requirements of more application scenarios. As we all know, permanent magnet motors can be divided into brushless and brushed types. So what are the differences between them? Let's make a comparison and analysis here.

The brushed part of the industrial ceiling fan permanent magnet motor is mainly composed of a stator, a rotor, carbon brushes, and other components. The stator has magnetic poles (wound or permanent magnet type), and the rotor has a winding. The rotating magnetic field generates rotational torque, thereby outputting kinetic energy. The brushes and commutator constantly come into contact and friction, playing the role of conducting and commutating during rotation. After being energized, a magnetic field is formed on the rotor. There is an angle between the magnetic poles of the stator and the rotor. The mutual attraction between the magnetic fields of the stator and the rotor causes the motor to rotate. Changing the position of the brushes can change the direction of the angle between the magnetic poles of the stator and rotor, thereby changing the rotation direction of the motor.

Brushed motors use mechanical commutation, with the magnetic poles fixed and the coils rotating. When the motor is working, the coils and commutator rotate while the magnets and carbon brushes do not. The alternating change in the direction of the coil current is completed by the commutator and brushes that rotate with the motor. The sliding friction will wear the carbon brushes, requiring periodic replacement. The on-off alternation between the carbon brush and the coil connection may cause electrical sparks and electromagnetic interference, which can interfere with electronic equipment.

The industrial ceiling fan uses a permanent magnet brushless motor, which mainly consists of a stator, rotor, and other components without carbon brushes. Electronic commutation is adopted, with the coils stationary and the magnetic poles rotating. A Hall element is used to sense 20% of the position of the permanent magnet. According to this perception, the current direction in the coil is timely switched by the electronic circuit to ensure the production of the correct direction of magnetic force to drive the motor.

The removal of brushes in the brushless motor is the most direct change, which eliminates the electrical sparks generated during the operation of the brushed motor. This greatly reduces the interference of electrical sparks on remote wireless devices. Without brushes, the frictional force during operation is greatly reduced, making the operation smooth and noise much lower. This advantage is a huge support for stable operation. Without brushes, the wear of the brushless motor is mainly on the bearings. From a mechanical point of view, the brushless motor is a maintenance-free motor.
Although the permanent magnet brushless motor is an upgraded and improved version of the permanent magnet brushed motor, they both have their advantages and disadvantages and are suitable for different application scenarios. As industrial ceiling fans are heavy and inconvenient to repair due to their high altitude and are often used in commercial public places with high requirements for noise and smooth operation, the permanent magnet brushless motor is more suitable for use in industrial ceiling fans.