Induction Motor

Three phase induction Induction Motor motors have a very simple construction made up of a stator covered with electromagnets, and a rotor composed 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 developed through the use of a three-stage current at the stators electromagnets. Therefore induces a current inside the rotor’s conductors, which in turns generates 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 basic and rugged in construction. They are more robust and can operate in virtually any environmental condition

Induction motors are cheaper in cost due to simple rotor construction, absence of brushes, commutators, and slip rings

They are free of maintenance motors unlike dc motors due to the lack of brushes, commutators and slip rings

Induction motors can be operated in polluted and explosive conditions as they don’t have brushes which can cause sparks

AC Induction motors are Asynchronous Machines and therefore the rotor does not change at the specific same speed because the stator’s rotating magnetic field. Some difference in the rotor and stator velocity is necessary to be able to create 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 operate effectively. Roboteq AC Induction controllers can be configured to operate in another of three modes:

Scallar (or Volts per Hertz): an Open loop mode in which a control 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 Speed and Torque control that works by optimizing the rotating field of the stator vs. this of the induced field in the rotor.

Discover this video from Learning Engineering for a visual illustration about how AC Induction Motors are constructed and function.