via：https://www.allaboutcircuits.com/news/historical-engineers-george-westinghouse-and-the-ac-power-grid/
AC Versus DC
After making natural gas distribution safe, Westinghouse set his eyes on the distribution of electricity. At the time, Thomas Edison's DC electrical grid was a popular model that was thought to revolutionize modern society. Edison's grid had a major flaw in it, however. The DC electrical grid could only distribute electricity about 2 kilometers away from its power source.
Westinghouse was almost the complete opposite of Edison in personality. While Edison was a showman who loved to talk himself and his inventions up, Westinghouse didn't even like to be photographed and was much more open to incorporating the ideas of other inventors. Even when Nikola Tesla worked for Edison, Edison went out of his way to discredit Tesla's alternating current. Westinghouse, however, made Tesla a central figure in the Westinghouse Electrical Company.
Seeing the limitations of the DC electrical grid, Westinghouse purchased the patent Gaulard and Gibbs' AC transformer, along with Tesla's AC induction motor, to create an AC electrical grid to transfer power up to thousands of miles using a concept similar to his natural gas valve system. The transformer served as a reduction valve for electricity.
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