Brushless motor is composed of motor body and driver, which is a typical mechatronics product. The stator winding of the motor is mostly made of three-phase symmetrical star connection, which is very similar to the three-phase asynchronous motor.
A magnetized permanent magnet is attached to the rotor of the motor, and a position sensor is installed in the motor to detect the polarity of the rotor.
The brushless driver is composed of power electronic devices and integrated circuits, etc. Its function is to accept the start, stop and brake signals of the motor to control the start, stop and brake of the motor; The position sensor signal and positive and negative turning signal are accepted to control the on-off of each power tube of the inverter bridge to generate continuous torque; Receive speed instructions and speed feedback signals to control and adjust the speed; Provide protection and display and more. Since the brushless motor is operated in an automatic control mode, it will not add a starting winding to the rotor like a synchronous motor started under frequency conversion speed regulation, and will not produce oscillation and out-of-step when the load changes.
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First of all, we must define the definition of ordinary motor, induction motor (induction motor) is generally used in the industrial field, the motor in normal life is generally brushed or brushless motor, so once again the ordinary motor is equivalent to the brush motor to answer.
Brush motor :(1) large friction, large loss; (2) large heat, short life; (3) Low efficiency and small output power;
Advantages of brushless motor :(1) no brush, low interference; (2) Low noise, smooth operation; (3) Long life and low maintenance cost