Three phase induction motors employ a simple construction made up of a stator covered with electromagnets, and a rotor made up of Induction Motor conductors shorted at each end, arranged as a “squirrel cage”. They focus on the theory of induction in which a rotating electro-magnetic field it produced through the use of a three-phase current at the stators electromagnets. Therefore induces a current within the rotor’s conductors, which in turns creates 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 structure. They are better quality 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 could be operated in polluted and explosive conditions as they don’t have brushes that may cause sparks
AC Induction motors are Asynchronous Machines meaning that the rotor does not switch at the precise same speed because the stator’s rotating magnetic field. Some difference in the rotor and stator acceleration is necessary to be able to produce the induction into the rotor. The difference between your two is named the slip. Slip must be kept within an optimal range to ensure that the motor to use effectively. Roboteq AC Induction controllers can be configured to operate in another of three modes:
Scallar (or Volts per Hertz): an Open loop mode where a command causes a simultaneous, fixed-ratio Frequency and Voltage alter.
Controlled Slip: a Closed Loop speed where voltage and frequency are managed to keep slip 
inside a narrow range while working 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.
Observe this video from Learning Engineering for a visual illustration on how AC Induction Motors are constructed and function.