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Changzhou High-Efficiency Motors Co., Ltd.
Changzhou High-Efficiency Motors Co., Ltd.

The difference between brushed and brushless dc motor

What is the difference between brushed dc motors and brushless dc motors? Most people may not know about the difference between brushed dc and brushless dc motors. Here is a detailed introduction to Hemotors Motor.


(1) Brushed dc motor

The brushed dc motor adopts mechanical commutation, the magnetic pole does not move, and the coil rotates. When the motor is working, the coil and the commutator rotate, but the magnetic steel and the carbon brush do not rotate. The alternating change of the current direction of the coil is accomplished by the commutator and brush that rotate with the motor.


In a brushed dc motor, the process is to arrange the two power input ends of each group of coils into a ring in turn and separate them with insulating materials to form a cylinder-like thing, which is integrated with the motor shaft. Through two small columns (carbon brushes) made of carbon elements, under the action of spring pressure, from two specific fixed positions, press the two points on the upper coil power input ring cylinder to energize a group of coils. As the motor rotates, different coils or different two poles of the same coil are energized at different times, so that the N-S poles of the magnetic field generated by the coils and the N-S poles of the closest permanent magnet stator have a suitable angle difference. Repel each other, generate force, and push the brushed motor to rotate. The carbon electrode slides on the coil terminal like a brush on the surface of the object, so it is called a carbon "brush".


(2) Brushless dc motor

The brushless dc motor adopts electronic commutation, the coil does not move, and the magnetic pole rotates. The brushless dc motor uses a set of electronic equipment to sense the position of the magnetic pole of the permanent magnet through the Hall element. According to this perception, the electronic circuit is used to switch the direction of the current in the coil in time to ensure that the magnetic force in the correct direction is generated to drive the motor. Eliminates the disadvantages of brushed motors. It is widely used in various fields, such as the electronic alarm clock of the battery car, which makes full use of these functions.


The brushless dc motor consists of a motor body and a driver and is a typical mechatronic product. Because the brushless dc motor operates in a self-controlled manner, it will not add a starting winding to the rotor like an asynchronous motor with a heavy load starting under variable frequency speed regulation, nor will it cause oscillation and loss of step when the load changes abruptly.