Three phase induction motors have a very simple construction composed of a stator covered with Induction Motor china 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 produced through the use of a three-phase current at the stators electromagnets. Therefore induces a current inside the rotor’s conductors, which in turns creates rotor’s magnetic field that tries to follow stator’s magnetic field, pulling the rotor into rotation.
Benefits of AC Induction Motors are:
Induction motors are basic and rugged in structure. They are more robust and can operate in any environmental condition
Induction motors are cheaper in expense due to simple rotor construction, absence of brushes, commutators, and slide rings
They are free of maintenance motors unlike dc motors because of the absence of brushes, commutators and slip rings
Induction motors can be operated in polluted and explosive conditions as they don’t have brushes that may cause sparks
AC Induction motors are Asynchronous Machines and therefore the rotor does not switch at the exact same speed because the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary to be able to make the induction into the rotor. The difference between the two is called the slip. Slip must be kept within an optimal range in order for the motor to use efficiently. Roboteq AC Induction controllers could be configured to operate in one of three modes:
Scallar (or Volts per Hertz): an Open up loop mode where a command causes a simultaneous, fixed-ratio Frequency and Voltage change.
Controlled Slip: a Closed Loop speed where voltage and frequency are managed in order to keep slip inside a narrow range while operating at a desired speed.
Field Oriented Control (Vector Drive): a Closed Loop Speed and Torque control that functions by optimizing the rotating field of the stator vs. this of the induced field in the rotor.
Observe this video from Learning Engineering for a visual illustration on how AC Induction Motors are constructed and work.