Ferraris' motor

In 1885, Galileo Ferraris demonstrated an induction motor that also involved using two pairs of electromagnets to create a rotating magnetic field, though he did this independently of Baily.

More significantly, however, he proposed creating a true rotating magnetic field for it by supplying two sine wave alternating currents 90° apart.

In 1885, Professor Ferraris constructed the motor depicted in plan in Fig 1, which was not, however, publicly shown till 1888.

It consisted of two pairs of electromagnets A A and B B', having a common yoke made by winding iron wire around the exterior.

Two alternate currents differing in phase were led into these two circuits, and the pivoted central body was observed to revolve.

Ferraris's first publication was in March 1888, entitled Electrodynamic rotations produced by means of alternate currents.

This article incorporates text from this source, which is in the public domain: Polyphase Electric Currents and Alternate-Current Motors.