Principle of induction motor
Release time:
2021-11-22 19:13
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Principle of induction motor
The induction motor is also called "asynchronous motor", that is, the rotor is placed in a rotating magnetic field, and under the action of the rotating magnetic field, a rotating torque is obtained, so the rotor rotates.
The appearance and internal structure of induction motors The rotor is a rotatable conductor, usually in the shape of a squirrel cage. The stator is the non-rotating part of the motor, and its main task is to generate a rotating magnetic field. The rotating magnetic field is not realized by mechanical methods. Instead, alternating current is passed through several pairs of electromagnets to cyclically change the magnetic pole properties, so it is equivalent to a rotating magnetic field. This kind of motor does not have brushes or slip rings like DC motors. There are single-phase motors and three-phase motors depending on the type of AC used. Single-phase motors are used in washing machines, electric fans, etc.; three-phase motors are used as power for factories equipment. Through the relative movement between the rotating magnetic field generated by the stator (its speed is the synchronous speed n1) and the rotor winding, the rotor winding cuts the magnetic induction line to generate an induced electromotive force, thereby causing an induced current in the rotor winding. The induced current in the rotor winding interacts with the magnetic field to generate electromagnetic torque, which makes the rotor rotate. As the rotor speed gradually approaches the synchronous speed, the induced current gradually decreases, and the generated electromagnetic torque is also reduced accordingly. When the asynchronous motor is working in the motor state, the rotor speed is less than the synchronous speed. In order to describe the difference between the rotor speed n and the synchronous speed n1, slip is introduced.
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Steady state model control method
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With the development of power electronics technology, microelectronics technology, digital control technology and control theory, the dynamic and static characteristics of the AC drive system are completely comparable to the DC drive system.
The structure of a synchronous motor is roughly the same as that of an alternator. The basic difference between it and an induction motor is that its rotor is a protruding magnetic pole with a coil, and another exciter is used to pick up the direct current and the alternating current)
The induction motor is also called "asynchronous motor", that is, the rotor is placed in a rotating magnetic field, and under the action of the rotating magnetic field, a rotating torque is obtained, so the rotor rotates.
AC motors are composed of a stator and a rotor
AC motors are composed of a stator and a rotor. AC motors are divided into two types: synchronous AC motors and induction motors. In both motors, the stator-side winding is supplied with alternating current to generate a rotating magnetic field, but the rotor winding of a synchronous AC motor usually requires an excitation machine to supply direct current (excitation current); while the induction motor does not need to be supplied with current to the rotor winding.
An AC motor is a device that converts AC electrical energy into mechanical energy. The AC motor is mainly composed of an electromagnet winding or distributed stator winding to generate a magnetic field and a rotating armature or rotor. The motor is made by using the phenomenon that the energized coil rotates under a force in a magnetic field. AC motors are divided into two types: synchronous AC motors and induction motors.
