Three phase induction motors employ a simple construction composed of a Induction Motor stator protected with electromagnets, and a rotor made up of conductors shorted at each end, arranged as a “squirrel cage”. They work on the theory of induction where a rotating electro-magnetic field it made through the use of a three-stage current at the stators electromagnets. Therefore induces a current in the rotor’s conductors, which in turns generates rotor’s magnetic field that tries to check out stator’s magnetic field, pulling the rotor into rotation.
Benefits of AC 
Induction Motors are:
Induction motors are basic and rugged in building. They are better quality and can operate in virtually any environmental condition
Induction motors are cheaper in expense because of simple rotor construction, absence of brushes, commutators, and slide rings
They are maintenance free motors unlike dc motors due to the lack of brushes, commutators and slip rings
Induction motors could be operated in polluted and explosive environments as they don’t have brushes that may cause sparks
AC Induction motors are Asynchronous Machines meaning that the rotor will not convert at the precise same speed because the stator’s rotating magnetic field. Some difference in the rotor and stator quickness is necessary in order to generate the induction in to the rotor. The difference between the two is named the slip. Slip should be kept in a optimal range in order for the motor to use effectively. Roboteq AC Induction controllers could be configured to operate in one of three modes:
Scallar (or Volts per Hertz): an Open loop mode where a order causes a simultaneous, fixed-ratio Frequency and Voltage modify.
Controlled Slip: a Closed Loop speed where voltage and frequency are controlled to keep slip inside a narrow range while working at a desired speed.
Field Oriented Control (Vector Drive): a Closed Loop Rate 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 work.