Asynchronous motors are the most preferred motors because they are inexpensive, require little maintenance and do not cause arc during operation. Their efficiency is high, the engine speed changes very little with the load. The reason why these motors are called asynchronous is that the rotation speed of the magnetic field formed in the stator windings and the rotation speed of the rotor are not the same. The speed of the rotor is always less than the speed of the magnetic field. For him, these motors are called asynchronous motors, which means they are not compatible.