Most AC motors rely on polar electromagnetic fields generated and separated on both sides to rotate the rotor. In an asynchronous motor, spur gear the stator’s electromagnetic field is caused by an alternating current supply. The rotor is not directly connected to any power source, and thus develops an internal electric current through induction. This is exactly the same process used to generate current in the secondary windings of a transformer. The current produced in the rotor then generates its own electromagnetic field, and the rotor begins to rotate.

The asynchronous motor is ideal for use on heavier machines due to its robustness. It has the advantage of low cost for acquisition and maintenance and long service life. The field generated in the rotor is not supplied by the direct introduction of a current, but rather by induction of the current transformer of the stator adjacent to the electromagnetic field. The stator of an asynchronous motor has a number of windings or coils arranged along its inner surface, each of which includes a set of electrical connections on the outside of the frame.