The basic knowledge of ac asynchronous brushless dc motor | encyclopedia of BLDC motor | the brushless dc motor in the south of anhui's official website

The operation of ac asynchronous motor is a leading ac voltage motor, widely used in electric fans, refrigerators, washing machines, air conditioner, hair dryers, vacuum cleaners, lampblack machine, dishwasher, electric sewing machine, food processing machine and other household electrical appliances and various kinds of electric tools, small mechanical and electrical equipment. Ac asynchronous motor is divided into ac induction motor and motor commutator. Induction motor is divided into single-phase asynchronous motor, ac/dc motor and repulsion motor. The speed of the brushless dc motor ( The rotor speed) Less than the speed of a rotating magnetic field, which call for asynchronous brushless dc motor. It and sensor brushless dc motor is basically the same. s=( ns - n) /ns。 S for the slip, ns for magnetic speed, n for the rotor speed. Basic principles: 1, when three phase asynchronous access three-phase ac power brushless dc motor, stator winding through the three phase of three-phase current of three-phase magnetomotive force ( The stator rotating magnetomotive force) And produce a rotating magnetic field. 2, the conductor of the rotating magnetic field and rotor relative cutting movement, according to the principle of electromagnetic induction, the rotor conductors produce inductive electromotive force and inductive current. 3, according to the law of electromagnetic force, rotor of current-carrying conductor in magnetic field by electromagnetic force, the formation of electromagnetic torque and drive the rotor rotation, when the motor shaft with mechanical load, then the output mechanical energy outward. Asynchronous brushless dc motor is a kind of ac brushless dc motor, the rotating speed and load to the power grid frequency ratio is not constant relations. Also with the size of the load change. The greater the load torque, rotor speed is lower. Asynchronous brushless dc motor including induction brushless dc motor, brushless doubly-fed asynchronous ac dc motor and brushless dc motor commutator. Sensor brushless dc motor, the most widely used in the case of not cause misunderstanding or confusion, general induction brushless dc motor can be said for the asynchronous brushless dc motor. General asynchronous brushless dc motor stator windings to communication network, and the rotor windings without other power supply connection. Therefore, it has simple structure, manufacture, use and maintenance is convenient, reliable operation and quality is small, low cost advantages. Asynchronous brushless dc motors have higher efficiency and better operation of the work, from no-load to full load within the scope of nearly constant speed operation, the majority of industrial and agricultural production to meet the mechanical transmission requirements. Asynchronous BLDC motor also facilitate derived into various protection forms, to adapt to the needs of different environmental conditions. Asynchronous brushless dc during, must draw on the grid reactive excitation power, makes the power factor of power grid as bad. Therefore, to drive the ball mill, such as high power, low speed compressor mechanical equipment, often using synchronous brushless dc motor. Due to the induction of brushless dc motor speed rotating magnetic field with its slip relationship to a certain extent, its control performance is poor ( Except for ac commutator motor) 。 To request a broad and smooth speed range of transportation machinery, rolling mill, large machine tools, printing, dyeing and paper making machinery, etc. , using dc brushless dc motor is more economic and convenient. But with the development of power electronics and ac speed regulating system, suitable for wide speed range of the asynchronous current brushless dc motor speed control performance and economy can be comparable with dc brushless dc motor.