Three phase induction motors employ a simple construction made up of a stator protected with electromagnets, and a rotor composed of conductors shorted at each end, arranged as a “squirrel cage”. They work on the basic principle of induction in which a rotating electro-magnetic field it developed by applying a three-stage current at the stators electromagnets. Therefore induces a current inside the rotor’s conductors, which in turns produces rotor’s magnetic field that attempts to check out stator’s magnetic field, pulling the rotor into rotation.

Great things about AC Induction Motors are:

Induction motors are basic and rugged in building. They are better quality and can operate in any environmental condition

Induction motors are cheaper in expense because of simple rotor construction, absence of brushes, commutators, and slip rings

They are free of maintenance motors unlike dc motors due to the absence of brushes, commutators and slip rings

Induction motors could be operated in polluted and explosive environments as they don’t have brushes which can cause sparks

AC Induction motors are Asynchronous Devices and therefore the rotor will not switch at the precise same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary in order to develop the induction into the rotor. The difference between the two is called the slip. Slip must be kept in a optimal range to ensure that the motor to operate efficiently. Roboteq AC Induction Induction Motor china controllers can be configured to operate in another of three modes:

Scallar (or Volts per Hertz): an Open loop mode where a command causes a simultaneous, fixed-ratio Frequency and Voltage alter.

Controlled Slip: a Closed Loop speed where voltage and frequency are controlled to keep slip within a narrow range while running at a preferred speed.

Field Oriented Control (Vector Drive): a Closed Loop Quickness and Torque control that functions by optimizing the rotating field of the stator vs. this of the induced field in the rotor.

Find this video from Learning Engineering for a visual illustration about how AC Induction Motors are constructed and function.