Conception
Asynchronous motor, also known as induction motor, is an AC motor that converts electromechanical energy into mechanical energy by the interaction of the air gap rotating magnetic field and the rotor winding induced current to generate electromagnetic torque.The pump often uses the three-phase asynchronous motor as the driving force.
The three-phase asynchronous motor is a kind of induction motor, which is a type of motor that is powered by simultaneously connecting 380V three-phase alternating current (phase difference 120 degrees).
Since the rotating magnetic field of the three-phase asynchronous motor rotates in the same direction and at different rotational speeds, there is a slip ratio, so it is called a three-phase asynchronous motor.

Classification 
1. The cage rotor
The asynchronous motor of the cage rotor has simple structure, reliable operation, light weight and low price, and has been widely used. 
The main disadvantage is that the speed regulation is difficult.

2. The wound rotor
The wound rotor three-phase asynchronous motor is also provided with a three-phase winding and connected to an external varistor through a slip ring and a brush.
Adjusting the varistor resistance improves the starting performance of the motor and regulates the speed of the motor.

Features
1.Small size and low weight.
2.It is easy to achieve high-speed rotation with a speed exceeding 10000r/min.
3.High efficiency at high speed and low torque.
4.High torque at low speed and a wide range of speed control.
5.Strong reliability.
6.Lower cost.
7.The simplification of the control device.