Ferraris was an Italian physicist and professor of technical physics at the Industrial Museum of Turin, now the Turin Polytechnic. He'd already worked on early long-distance AC transmission experiments in Italy years before the discovery he's actually remembered for.
What he actually did
Starting in 1885, working independently of Tesla and without any knowledge of Tesla's parallel research in the United States, Ferraris developed the idea of generating a true rotating magnetic field using two stationary coils positioned at right angles, fed by alternating currents 90 degrees out of phase. He formally presented the mathematical theory to the Turin Academy of Sciences on March 18, 1888, just weeks before Tesla's own patent was granted that May.
What makes him great
Two people arrived at essentially the same fundamental discovery, on almost the exact same timeline, on opposite sides of an ocean, with no knowledge of each other's work. Tesla patented his version and licensed it to Westinghouse. Ferraris published his openly and never patented it at all, apparently believing scientific knowledge like this belonged in the open rather than owned by any one person or company. He died young, in 1897 at age 49, only three months after being named a senator of the Kingdom of Italy. In January 2021, the IEEE formally recognized his work with a dedicated milestone honor, well over a century after the fact, finally giving him something closer to equal billing with Tesla for the same discovery.
Sources
- Engineering and Technology History Wiki (ETHW), "Milestones: Rotating Fields and Early Induction Motors, 1885-1888."
- Wikipedia, "Galileo Ferraris."
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