Three phase induction motors have a very simple construction composed of a stator covered with electromagnets, and a rotor made up of conductors shorted at each end, arranged as a “squirrel cage”. They focus on the basic principle of induction in which a rotating electro-magnetic field it created by applying a three-phase current at the stators electromagnets. Therefore induces a current within the rotor’s conductors, which in turns generates 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 structure. 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 slide rings
They are maintenance free motors unlike dc motors because of the absence of brushes, commutators and slip rings
Induction motors could be operated in polluted and explosive environments as they do not have brushes that may cause sparks
AC Induction motors are Asynchronous Machines and therefore the rotor will not convert at the precise same speed as the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary to be able to create the induction in to the rotor. The difference between the two is named the slip. Slip should be kept in a optimal range to ensure that the motor to operate effectively. Roboteq AC Induction controllers could be configured to operate in one of three modes:
Scallar (or Volts per Hertz): an Open loop mode in which 
a order causes a simultaneous, fixed-ratio Frequency and Voltage change.
Controlled Slip: a Closed Loop speed where voltage and frequency are controlled to keep slip inside a narrow range while Induction in Motor working at a preferred speed.
Field Oriented Control (Vector Drive): a Closed Loop Swiftness and Torque control that works 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 about how AC Induction Motors are constructed and work.