Three phase induction motors have a very simple construction composed of a stator protected with electromagnets, and a rotor composed of conductors shorted at each end, arranged as a “squirrel cage”. They focus on the basic principle of induction where a rotating electro-magnetic field it developed through the use of a three-stage current at the stators electromagnets. This in turn induces a current in the rotor’s conductors, which in turns produces rotor’s magnetic field that tries to check out stator’s magnetic field, pulling the rotor into rotation.
Great things about AC Induction Motors are:
Induction motors are simple and rugged in building. They are more robust and can operate in virtually any environmental condition
Induction motors are cheaper in cost due to simple rotor construction, lack of brushes, commutators, and slip rings
They are free of maintenance motors unlike dc motors because of 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 and therefore the rotor does not change at the specific same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator quickness is necessary in order to generate the induction into the rotor. The difference between the two is called the slip. Slip should be kept in a optimal range in order for the motor to operate efficiently. Roboteq AC Induction controllers could be configured to operate in another of three modes:
Scallar (or Volts per Hertz): an Open up loop mode in which a order causes a simultaneous, fixed-ratio Frequency and Voltage Induction Motor modify.
Controlled 
Slip: a Shut Loop speed where voltage and frequency are managed in order to keep slip inside a narrow range while operating at a preferred speed.
Field Oriented Control (Vector Drive): a Closed Loop Acceleration and Torque control that functions by optimizing the rotating field of the stator vs. this of the induced field in the rotor.
Discover this video from Learning Engineering for a visual illustration on how AC Induction Motors are constructed and function.