Three phase Induction Motor china induction motors employ a simple construction made up of a stator covered with electromagnets, and a rotor made up of conductors shorted at each end, arranged as a “squirrel cage”. They work on the principle of induction where a rotating electro-magnetic field it produced by applying a three-stage current at the stators electromagnets. Therefore 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 basic and rugged in construction. They are more robust and can operate in any environmental condition
Induction motors are cheaper in cost because of simple rotor construction, lack of brushes, commutators, and slide rings
They are maintenance free motors unlike dc motors due to the absence of brushes, commutators and slip rings
Induction motors can be operated in polluted and explosive environments as they don’t have brushes that may cause sparks
AC Induction motors are Asynchronous Devices meaning that the rotor will not switch at the exact same speed as the stator’s rotating magnetic field. Some difference in the rotor and stator speed is necessary to be able to generate the induction into the rotor. The difference between your two is called the slip. Slip must be kept in a optimal range in order for the motor to operate efficiently. Roboteq AC Induction controllers can 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 managed to keep slip within a narrow range while working at a desired 
speed.
Field Oriented Control (Vector Drive): a Closed Loop Swiftness 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.