What is the working principle of three-phase asynchronous motor?
Source：Nanyang Electric Visit：535 Pushtime：2018-08-11 15:58:04 【Print】【Return】【Font：Large Middle Small】
Three-phase asynchronous motor is a kind of motor powered by 380V three-phase AC power supply (phase difference 120 degrees). Because the rotor of three-phase asynchronous motor rotates with the stator rotating magnetic field in the same direction and at different rotating speeds, there is slip rate, so it is called three-phase asynchronous motor.
Three-phase asynchronous motor is an induction motor, after the stator into the current, part of the flux through the short-circuit loop, and in which the induction current.
The current in the short-circuit ring impedes the flux change, resulting in the phase difference between the flux produced by the part with and without the short-circuit ring, thus forming a rotating magnetic field. After power-on and start-up, the rotor winding induces electromotive force and current because of the relative motion between the rotor and the magnetic field, that is, the rotating magnetic field and the rotor have relative rotational speed, and the interaction with the magnetic field produces electromagnetic torque, which makes the rotor rotate and realizes energy transformation.
The working principle of three-phase asynchronous motor is:
Assuming that the rotation of the magnetic field is counterclockwise, this is equivalent to cutting the magnetic field lines clockwise relative to the permanent magnet in the direction of the induced current in the metal frame, as shown in the small circle in the figure.
At this point, the metal frame has become an electrified conductor, so it will be subject to the magnetic field force, the direction of the force can be judged by the left-hand rule. The two sides of the metal frame are subjected to two opposite forces f, which produce electromagnetic torque (magnetic torque) relative to the rotating axis, so that the metal frame in the closed metal frame rotates in the same direction as the magnetic field, but the permanent magnet rotates faster than the metal frame.