There can be little doubt that Tesla developed the modern usage of alternating current. Despite the "magical" overtones of my book, it relates clearly the "resistance" of the DC lobby [led by Edison-who was not an engineer]. In 1874, as a student, Tesla was apparently not impressed by a Gramme machine [DC Dynamo/Motor] and it's sparking commutator! "The professor explained that as long as electricity flowed in one direction, a commutator would be necessary to change the direction and sparking could not be avoided." Tesla felt that the use of alternating current could solve that one. "The professor informed Tesla that many men had experimented with alternating current and it was simply not feasible".
In 1891, after his 'friend' Westinghouse had used Tesla's polyphase system to monopolise electrical distribution, HIS own backers told him to destroy his connection with Tesla or face ruin. "Standing there before Westinghouse, Tesla smiled serenely and tore up his contract without a trace of bitterness. At that moment he was entitled to at least twelve million dollars in royalties."
Now here's a claim-"It has often been said that failure to pay royalties to Tesla proved to be the greatest handicap to scientific and industrial progress which the human race has ever experienced. After the financial setback 'engineered' by the Westinghouse money men, Tesla never again had sufficient funds to develope his inventions."
Dave W