ACmootorid

AC motors are electric machines that convert alternating-current energy into mechanical energy. They are widely used in industry and everyday devices due to their robustness and relatively simple construction. The two main families are induction motors (also called asynchronous motors) and synchronous motors. A third category, universal motors, can operate on AC supply and share some characteristics with DC motors, though they are less common in large installations.

Induction motors use a stator winding that creates a rotating magnetic field when powered by AC. This rotating field induces currents in the rotor, producing torque. The most common type is the squirrel-cage rotor, though wound-rotor variants exist for special applications. In induction motors, the rotor speed is slightly less than the synchronous speed set by the supply frequency, a difference called slip. Three-phase induction motors dominate industrial use because of their simplicity, ruggedness, and low maintenance. They cover a wide range of power ratings and are well suited for constant-speed applications.

Synchronous motors have rotors that are excited with a DC current or permanent magnets, causing the rotor to rotate at the same speed as the rotating magnetic field. They do not slip under normal operation, which makes their speed predictable and stable. Synchronous motors are used when precise speed and power factor control are important, such as in certain conveyors, mills, and large pumps. They can provide reactive power support, improving system efficiency when properly designed.

Control and efficiency: AC motors are typically controlled by varying supply frequency (variable-frequency drives) or by soft-start methods. They come in a range of efficiency ratings and standards (IE1–IE4 in many regions). Common advantages include simplicity, durability, and low maintenance, while limitations include less flexible speed control for induction motors and higher cost for some synchronous configurations. Applications span fans, pumps, compressors, conveyors, and machine tools.