The Electric Motor

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Ask who invented the electric motor and the honest answer is that no single filing settles it, because the idea arrived in pieces across sixty years. Michael Faraday supplied the principle on 3 September 1821, spinning a wire around a magnet in a pool of mercury to show that a magnetic field could turn electricity into motion, but Faraday built a demonstration, not a machine anyone could put to work. The Hungarian physicist Anyos Jedlik took the next step in 1828, building a device with a stator, a rotor and a commutator, the three parts every later direct current motor would keep, though his work stayed largely unpublished outside Hungary. It was Moritz von Jacobi, a German engineer working in Russia, who built the motor usually credited as the first genuinely useful one: in May 1834 his design was strong enough to drive a small boat carrying fourteen passengers across the Neva River, a public demonstration that a magnet and a coil could do real mechanical work. None of these three ever built a business around the motor. That took another decade, and a different country entirely.

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

In 1837 the American blacksmith Thomas Davenport, working with his wife Emily Davenport, patented a commutated motor that reached six hundred revolutions per minute and could drive machine tools and even a small printing press. It was the first motor built with a shop, not a laboratory, in mind, and it still fell short of what industry needed: without a way to hold a steady speed under a changing load, an electric motor could not replace the belts and shafts a factory already trusted. That problem waited until 1886, when Frank Julian Sprague built the first motor that stayed at a nearly constant speed no matter how hard it was worked, the advance that finally let a factory place power wherever a machine stood rather than wherever a line shaft could reach. Sprague did not stop at the factory floor. In 1887 and 1888 he built the first successful electric streetcar system, carrying his own motor design out of the workshop and into the street, and from there into the subway. The distance between Jacobi's fourteen-passenger boat in 1834 and Sprague's city transit system in 1888 is the distance between a proof that an idea works and a proof that it pays.