The main parameters and the classification of three-phase asynchronous motor
The main parameters
Motor speed
In generator stator into the 3 alternating current, which produce a rotating magnetic field, rotating speed of n0. The number of the magnetic poles of P different, action of alternating current at the same frequency of f=50Hz, can produce differentsynchronous speed N0, n0=60f/p.
The rotor speed is lower than the rotating magnetic field and induction motor speed, itis basically the same. S= (ns-n) /ns. S is slip,
NS n for magnetic speed, rotor speed.
The motor torque
Symmetric 3 phase windings into symmetric 3 phase current, produce a rotating magnetic field, magnetic line cutting rotor windings, according to the principle of electromagnetic induction, the production of E and I in the rotor winding, rotor windingby the electromagnetic force in the magnetic field effect, namely the electromagnetic torque, rotating the rotor, rotor output mechanical energy, driven mechanical loadrotation up.
In AC motor, when the stator winding through the alternating current, armature MMF is established, it has a great effect on the energy conversion motor and operatingperformance. So the three-phase AC windings in three-phase AC generatingpulsating MMF, the magnetomotive force can be decomposed into two equal amplitude, speed the opposite rotating magnetomotive force in the air gap and, thusestablishing the positive rotation and the reverse rotation of the magnetic field and the. The two rotating magnetic field cutting rotor conductors respectively, and theinduced electromotive force and the induced current in the rotor conductor.
Produce the current and the magnetic field interaction is, anti electromagnetic torque.Forward electromagnetic torque in an attempt to make the rotor rotating; reverseelectromagnetic torque in an attempt to make the rotor reversal. The two torquesuperposition up is to promote the synthesis of torque motor rotation.
According to the structure and working principle
According to the electric motor according to the structure and working principle of different, can be divided into DC motor, induction motor and synchronous motor.
Synchronous motor can be divided into permanent magnet synchronous motor,reluctance synchronous motor and magnetic hysteresis synchronous motor.
Asynchronous motor can be divided into the induction motor and AC commutator motor. Induction motor is divided into three phase asynchronous motor, single-phaseasynchronous motor and shaded pole asynchronous motor etc.. Commutator motor is divided into single-phase series motor, AC and DC motor and repulsion motor.
DC motor according to the structure and working principle can be divided intobrushless DC motor and brushless DC motor. DC motor with a brush can be divided into permanent magnetic DC motor and electromagnetic DC motor. ElectromagneticDC motor is divided into a series DC motor, DC shunt motor, he excited DC motor and the compound wound DC motor. Permanent magnetic DC motor is divided into iron oxide of rare-earth permanent magnet DC motor, permanent magnet DC motor and Al Ni Gu Yongci DC motor.
According to the use
Can be divided into the drive motor and motor control.
Drive motor is divided into electric tools (including drilling, polishing, polishing, slotting,cutting and reaming tools such as) with motor, appliance (including washing machines,electric fans, refrigerators, air conditioners, tape recorders, video recorders, video machines, vacuum cleaners, camera, electric blowing wind, electric razor) motor and other general small machinery and equipment (including a variety of small tools, small machinery, medical equipment, electronic equipment and so on) motor.
Motor control is divided again for step motor and servo motor etc..
According to the running speed
According to the motor according to the running speed is different, can be divided into the high-speed motor, low speed motor, constant speed motor, adjustable speed motor.
Low speed motor is divided into gear motor, gear motor, the electromagnetic torque motor and claw pole synchronous motor.
Variable speed motor in addition to can be divided into constant speed motor, and stepless constant speed motor, step speed motor and a stepless speed changing motor, but also can be divided into electromagnetic adjustable speed motor, DCspeed regulating motor, PWM frequency conversion motor and switched reluctancemotor.
Synchronous speed rotor speed of asynchronous motor is always slightly below therotating magnetic field.
Synchronous motor rotor speed and load size independent and always keep thesynchronous speed.
According to the structure of a rotor
According to the motor according to the rotor structure is different, can be divided into the squirrel cage induction motor (the old standard called the squirrel cage asynchronous motor) and wound rotor induction motor (the old standard called the winding asynchronous motor).
Asynchronous motor cage rotor is simple, reliable operation, light weight, cheap,widely used, its main shortcoming is difficult to control.
Winding type three-phase asynchronous motor rotor and stator and the three-phase winding through setting and a slip ring and an electric brush and external rheostatconnection. Rheostat resistance can improve the motor starting performance andadjust the rotating speed of the motor.
According to the working power supply
According to the motor working power supply is different, can be divided into DCmotor and AC motor. The AC motor is divided into single phase motor and the three-phase motor.
According to the starting and operating mode
According to the motor according to the starting and operating in different ways, can be divided into the capacitor start capacitor type single-phase asynchronous motor,running capacitor type single-phase asynchronous motor, the starting operation ofsingle-phase asynchronous motor and phase splitting single-phase asynchronous motor.
