John Hopkinson

John Hopkinson was a British physicist and electrical engineer who invented the three wire, three phase system for distributing electrical power, patented in 1882. In 1883 he showed mathematically that two alternating current dynamos could be safely connected in parallel, resolving a problem that had long troubled electrical engineers and clearing the way for larger, interconnected generating stations. He also patented a series parallel method of electric motor control in 1881 that became important to the development of electric railways, and Hopkinson's law, the magnetic counterpart to Ohm's law, is named in his honor. He served as professor of electrical engineering at King's College London from 1890 and was twice president of the Institution of Electrical Engineers.