From 1777 to 1851, the Danish Hans Christian Öersted could not imagine that his simple experience would uncover the fundamental physical principle for the operation of the electric motor. Passing an electric current generated by a pile by a conductive wire, approaching a compass to that wire, the needle would move and align perpendicular to the wire. This confirmed that there was a magnetic field around the wire. https://www.mrosupply.com/motors/ac-motors/single-phase-motors/2525455_11022200_leeson/ The relation between electricity and magnetism was first established.
The French physicist André-Marie Ampère (1775-1836), a mathematician after learning about Öersted’s experiences, began to formulate the law of electromagnetism, and came to the conclusion that the lines of force generated by the electrified wire magnetic field) are circular, forming a sort of invisible cylinder around the conductor.
From 1791 to 1867, Englishman Michael Faraday also researched the connection between electricity and magnetism. He was a physicist and a chemist, but he did not have a good theoretical background, so he valued experience as proof of natural phenomena. Thanks to his methodical and intense experiences, in 1822 he was able to prove what a circular magnetic field was. Belgian engineer-inventor and inventor Zénobe Théophile Gramme built in 1869 an engine that also behaved as a generator – the reverse machine.