May 1888: Tesla Files His Patents for the Electric Motor

Electric motors came into their own only after the Serbian-born inventor came up with a marketable design based on alternating current

2 min read
opening illustration for Numbers Don't Lie column
Photo-illustration: Stuart Bradford

Electrical devices advanced by leaps and bounds in the 1880s, which saw the first commercial generation in centralized power plants, the first durable lightbulbs, the first transformers, and the first (limited) urban grids. But for most of the decade, advances in electric motors lagged behind.

Rudimentary DC motors date back to the 1830s, when Thomas Davenport of Vermont used his direct-current motors to drill iron and steel and to machine hardwood, and Moritz von Jacobi of St. Petersburg used his motors to power small paddle wheels on the Neva. But those battery-powered devices couldn’t compete with steam power. More than a quarter century passed before Thomas Edison finally commercialized a stencil-making electric pen, to duplicate office documents; it, too, was powered by a DC motor. As commercial electricity generation began to spread after 1882, electric motors became common, and by 1887 U.S. manufacturers were selling about 10,000 units a year, some of them operating the first electric elevators. All of them, however, ran on DC.

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Asad Madni and the Life-Saving Sensor

His pivot from defense helped a tiny tuning-fork prevent SUV rollovers and plane crashes

11 min read
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Asad Madni and the Life-Saving Sensor

In 1992, Asad M. Madni sat at the helm of BEI Sensors and Controls, overseeing a product line that included a variety of sensor and inertial-navigation devices, but its customers were less varied—mainly, the aerospace and defense electronics industries.

And he had a problem.

The Cold War had ended, crashing the U.S. defense industry. And business wasn’t going to come back anytime soon. BEI needed to identify and capture new customers—and quickly.

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