Brushless direct current motor (brushless DC motor) is a typical mechatronics product consisting of motor and drive. Brushless motor, also named commutatorless motor, is motor without brush or commutator(or collector ring). The three-phase symmetrical star connection method is often used in the stator winding of the motor, which is similar to three-phase asynchronous motor. The rotor of the gear motor is stuck with a magnetized permanent magnet. To test the polarity of the rotor for the motor, there is a position sensor installed in the motor. The drive is made up of power electronics and integrated circuit, with the functions of accepting start-up, stop and braking signals from the motor to control the corresponding motion of the motor, accepting signals of the position sensor and cw&ccw to control on-off of each power tube of inverter bridge, generating continuous torque, accepting signals of speed command and velocity feedback to control and adjust the speed, provide protection and display.
Brushless DC motor can be used with gear reducer. This integrated assembly product is brushless DC gear motor, also called gear reduction motor. The function of the gear motor is to provide low speed and high torque. Meanwhile, different reduction ratios of gear motor can provide different speed and torque, which greatly improves the utilization rate of brushless DC motor in the automation industry.
The Characteristics of Brushless DC Motor:
- Can replace speed regulation of direct current motor, inverter plus inverter motor and Asynchronous motor plus reducer.
- Has features of a traditional direct current motor, while canceling the structure of carbon brush and slip ring.
- Can run in low speed and high power and drive the large load directly.
- Small size, light weight, and strong driving force.
- Excellent torque characteristics, which leads to good performance in medium and low speed, high starting torque and low starting current
- Has infinite torque regulation, wide speed regulation range, and strong overload capacity.
- Soft start & stop and good braking characteristics can save the original mechanical braking or electromagnetic braking device
- great reliability, stability and adaptability, easy to maintain.
- Bump and vibration resistance, low noise, smooth running, long service life.
- no sparks, suitable to the explosive occasion for it’s explosion-proof.
- Trapezoidal wave magnetic field motor and sinewave magnetic field motor are alternative according to requirements
- High efficiency. The motor itself has no excitation loss and carbon brush loss. The comprehensive electricity saving rate can reach 20%~60%.
Applications of Brushless DC motor:
Office Computer Equipment & Consumer Electronics
This is the field where brushless DC motor is the most widely used. Brushless DC motor can be seen in the driving control of main shafts and accessory movements of devices like printer, fax machine, duplicator, HDD, floppy drive, movie camera and tape recorder which are common in our life.
Following the development of technology and research on brushless DC motor, The application range of brushless DC motor in industry manufacturing expands and gradually becomes the development mainstream of industrial motors. There have been significant benefits in research and try on reducing production costs and improving running efficiency. Many manufacturers provide motor in different sizes to meet the needs of different drive systems. Brushless DC motor involves industry manufacturing including textile, metallurgy, printing, automatic production line, and numerical control machine tool at the present stage.
The application of the brushless DC motor is normal, being used to mini blood pump that drives the artificial heart. In China, apply brushless DC motor to a high-speed centrifuge for high-speed surgical instruments and infrared laser modulator for thermal imager and thermometer.
A normal family car needs 20-30 permanent magnet motors, while a luxury car needs 59. Besides the core engine, the motor can be seen in components like wiper, electric door, automobile air conditioner, and power window. With the automobile industry developing towards energy conservation and environmental protection, the motor used needs to meet the standards of high efficiency and low energy consumption. Brushless DC motor with features of low noise, long service life, no sparks, convenient centralized control can satisfy requirements above. Following the development of speed regulation technology, brushless DC motor will have a wider application on the automobile industry.
Frequency conversion technology which has been popularized occupies most of the consumer market as the symbol of home application. Receiving the favor of manufacturers, DC frequency conversion has a tendency to take the place of AC frequency conversion. Intrinsically, the transform is the transition of electric motors used in household appliances from induction motors to brushless DC motors and their controllers, meeting the requirements of energy conservation, environmental protection, low noise and high comfort. The developing direction of brushless DC motor is the same as that of technology including power electronics, sensor and control theory. Brushless DC motor is the product of a combination of various technologies, and its development depends on the innovation and improvement of the technologies associated with it.