The working foundation of electric motors is the principle of magnetic force where an inductor circuit called a stator, generates a fixed magnetic field so that the induced circuit called the rotor, enters into motion when being trodden by electric current. One of the precursors in the study of engines was Michael Faraday. In 1822, during his experiments, he saw the emergence of a circular motion by working out a circuit in series with a battery of direct current, magnets and two containers filled with mercury.

In one of the containers, Faraday secured a bar magnet in an upright position and preserved a moving wire immersed in the mercury. https://www.mrosupply.com/couplings-collars/elastomer-couplings/5002443_017129_dodge/ When closing the circuit, electrical current was constituted and the mobile wire began to rotate around the magnetized bar. In the other vessel, Faraday preserved the fixed wire and the movable magnet. Thus, upon closing the circuit, the magnet began to rotate around the fixed wire. Faraday associated these movements with the action of the magnetic field.

The machines that transform electrical energy into rotational mechanical energy are called electric motors and with the inventives of the relationships between electricity, magnetism and motion, it was possible to make electric motors of direct and alternating current, single phase and three phase.