Three phase induction motors have a very simple construction composed of a stator covered with electromagnets, and a rotor composed of conductors shorted at each end, arranged as a “squirrel cage”. They work on the principle of induction in which a rotating electro-magnetic field it produced by applying a three-phase current at the stators electromagnets. This in turn induces a current inside 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.
Benefits of AC Induction Motors are:
Induction motors are simple and rugged in Induction Motor structure. They are better quality and can operate in any environmental condition
Induction motors are cheaper in expense because of simple rotor construction, absence of brushes, commutators, and slide rings
They are maintenance free motors unlike dc motors because of the lack of brushes, commutators and slip rings
Induction motors can be operated in polluted and explosive environments as they do not have brushes which can cause sparks
AC Induction motors are Asynchronous Machines meaning that the rotor will not turn at the precise same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary to be able to develop the induction into the rotor. The difference between your two is named the slip. Slip should 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 up loop mode in which a control causes a simultaneous, fixed-ratio Frequency and Voltage change.
Controlled Slip: a Closed Loop speed where voltage and frequency are controlled in order to keep slip inside a narrow range while running at a desired speed.
Field Oriented Control (Vector Drive): a Closed Loop Velocity and Torque control that functions by optimizing the rotating field of the stator vs. this of the induced field in the rotor.
See this video from Learning Engineering for a visual illustration on how AC Induction Motors are constructed and work.