The first electric motors were small instruments for laboratory demonstrations rather than machines capable of supplying energy for practical applications.

In the first half of the nineteenth century, there were many proposed models of motors powered by the phenomena of attraction and repulsion between magnets and electromagnets. Often inspired by steam-engine design, they transformed alternating motion into rotary motion through systems composed of rocker arms and articulated arms. The motor invented by the Italian physicist Luigi Magrini in about 1840 belongs to this category. It consists of two electromagnets. Above each is a mobile iron bar held by parallel moving rods. The bars, in turn, are connected via mobile and eccentric arms to a brass flywheel.

When the current from a battery flows through one of the electromagnets, the bar near the magnet is attracted to it, transmitting its motion to the flywheel. As soon as the distance between the bar and the electromagnet reaches minimum, the electromagnet is automatically disabled. This is done by means of a commutator that simultaneously sends the current into the other electromagnet, which attracts the bar above it. And the cycle goes on, transforming the alternating horizontal motion of the moving bars into a continuous rotation of the flywheel.