What is a brushless motor and its characteristics



Xuheng Electronics


Xuheng Electronics

Release time: 2021-09-15


What is a brushless motor?
The brushless DC motor is composed of a motor body and a driver, and is a typical mechatronic product. Brushless motor refers to the motor without brush and commutator (or collector ring), also known as the commutatorless motor. As early as when the motor was born in the last century, the practical motor produced was a brushless form, that is, an AC squirrel cage asynchronous motor, which was widely used. However, asynchronous motors have many insurmountable defects, so that the development of motor technology is slow. Transistors were born in the middle of this century, so a brushless DC motor that uses transistor commutation circuits instead of brushes and commutators came into being. This new type of brushless motor is called an electronically commutated DC motor, which overcomes the defects of the first generation of brushless motors.
What is a brushless motor and its characteristics
Characteristics of brushless motor
1. Can replace DC motor speed regulation, frequency converter + frequency conversion motor speed regulation, asynchronous motor + speed reducer speed regulation;
2. It has the advantages of the traditional DC motor, and at the same time, the carbon brush and slip ring structure are eliminated;
3. With brake and dual steering functions;
4. Small size, light weight and large output;
5. Excellent torque characteristics, good torque performance at medium and low speeds, large starting torque and small starting current;
6. Stepless speed regulation, wide speed regulation range, strong overload capacity;
7. Soft start and soft stop, good braking characteristics, can save the original mechanical brake or electromagnetic brake device;
8. High efficiency, the motor itself has no excitation loss and carbon brush loss, eliminating multi-stage deceleration loss, and the comprehensive power saving rate can reach 20% ~ 60%.
9. High reliability, good stability, strong adaptability, simple repair and maintenance;
10. Resistant to bumpy vibration, low noise, small vibration, smooth operation and long life;
11. No sparks, especially suitable for explosive places, with explosion-proof type;
12. Trapezoidal wave magnetic field motor and sine wave magnetic field motor can be selected as required.
                       What is a brushless motor and its characteristics
Advantages of brushless motors
Different from brushed DC motors, brushless DC motors do not use mechanical brush devices, use square wave self-control permanent magnet synchronous motors, replace carbon brush commutators with Hall sensors, and use neodymium iron boron as the permanent magnet material of the rotor Compared with the traditional DC motor in performance, it has great advantages, and it is the most ideal speed-regulated motor today.
High efficiency, low energy consumption, low noise, long life, high reliability, servo control, stepless frequency conversion speed regulation, relatively low cost and easy to use.
The stator windings of brushless DC motors are mostly made into three-phase symmetrical star connection, which is very similar to three-phase asynchronous motors. The rotor of the motor has magnetized permanent magnets. In order to detect the polarity of the rotor of the motor, a position sensor is installed in the motor. The driver is composed of power electronic devices and integrated circuits. Its functions are: to accept the start, stop and brake signals of the motor to control the start, stop and brake of the motor; to accept the position sensor signal and the forward and reverse signals to control the reverse The on-off of the power tubes of the variable bridge produces continuous torque; accepts speed commands and speed feedback signals to control and adjust the speed; provides protection and display, etc.
Brushless DC motors are widely used in household appliances, automotive parts, power tools, office automation, industrial and commercial equipment, medical equipment, personal care, robots and many other industries.