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July 10, 2020

Three phase induction motors have a very simple construction made up of a stator protected with Induction Motor electromagnets, and a rotor composed of conductors shorted at each end, arranged as a “squirrel cage”. They work on the basic principle of induction where a rotating electro-magnetic field it made through the use of a three-stage current at the stators electromagnets. Therefore induces a current in 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.

Benefits of 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 because of simple rotor construction, absence of brushes, commutators, and slide rings

They are free of maintenance 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 which can cause sparks

AC Induction motors are Asynchronous Devices meaning that the rotor does not turn at the precise same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary in order to create the induction into the rotor. The difference between your two is called the slip. Slip must be kept within an optimal range to ensure that the motor to operate efficiently. Roboteq AC Induction controllers could be configured to operate in one of three modes:

Scallar (or Volts per Hertz): an Open up loop mode in which a order causes a simultaneous, fixed-ratio Frequency and Voltage alter.

Controlled Slip: a Shut Loop speed where voltage and frequency are managed to keep slip inside a narrow range while running 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.

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