Three phase induction motors employ a simple construction composed of a stator protected 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 in which a rotating Induction in Motor electro-magnetic field it made through the use of a three-phase current at the stators electromagnets. Therefore induces a current inside the rotor’s conductors, which in turns generates rotor’s magnetic field that attempts to follow stator’s magnetic field, pulling the rotor into rotation.

Great things about AC Induction Motors are:

Induction motors are basic and rugged in building. They are more robust and can operate in virtually any environmental condition

Induction motors are cheaper in expense because of simple rotor construction, absence of brushes, commutators, and slip rings

They are maintenance free motors unlike dc motors because of 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 does not switch at the specific same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator velocity is necessary to be able to develop the induction into the rotor. The difference between your two is named 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 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 alter.

Controlled Slip: a Shut Loop speed where voltage and frequency are controlled in order to keep slip within a narrow range while running 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 about how AC Induction Motors are constructed and work.