The induction motor is a type of electric motor that works from two rotating magnetic fields. It is a device widely used in industrial activities, especially those involving electric power generation. Of structure and operation considered simple, the three-phase induction motor consists basically of a rotor (moving part of the motor) and a stator ( fixed part) that operate simultaneously, in addition to a space between these two structures – which is called the air gap.
Both rotor and stator are composed of thin, ring-shaped magnetic steel plates which are treated in a way to reduce losses of the magnetic field. The stator is fixed to the motor housing and has the function of conducting the energy and transforming it into an electric one. The rotor, in turn, is a structure that revolves around its own axis, producing rotation and energy. The rotor and stator structures are assembled from a common axis through which a three-phase winding passes that allows the passage of the magnetic flux which, in turn, forms three interconnected symmetrical circuits. The result is a star or triangle interconnection.
Types of Three Phase Motors
Three-phase motors can be asynchronous or synchronous. The asynchronous models are manufactured in different powers and speeds to meet the standard voltages of the electrical network: 220V, 380V, 440V or 760V. This type of engine is the most used in industries, and offers better operating conditions than single-phase motors – which require start-up assistance. Synchronous three-phase motors are machines that promote the transformation of the electric energy received into mechanical energy to move a certain engine or machinery.
The induction motor has no brushes, so it does not generate electromagnetic interference. It also has no permanent magnets, or switch rings simplifying construction, and is controlled only by controlling the input frequency. The three-phase motor can start on its own. The single phase motor is used in low power applications. These engines are used in:
- Eletric cars;
- Industrial applications;
- Business Center;
- Low power home appliances