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Three phase 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 focus on the theory of induction where a rotating electro-magnetic field it produced through the use of a three-phase current at the Induction in Motor stators electromagnets. This in turn induces a current within 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.

Great things about AC Induction Motors are:

Induction motors are simple and rugged in building. They are more robust and can operate in virtually 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 because of the lack 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 meaning that the rotor does not convert at the specific same speed as the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary in order to make the induction into the rotor. The difference between your two is named the slip. Slip should be kept within an optimal range in order for 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 where a command causes a simultaneous, fixed-ratio Frequency and Voltage change.

Controlled Slip: a Shut Loop speed where voltage and frequency are managed to keep slip within a narrow range while running at a preferred 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 about how AC Induction Motors are constructed and function.