Tesla

In 1884, a 32-year-old Serbian engineer, Nikola Tesla, arrived in the USA, who, at the behest of Thomas Alva Edison was to increase the capacity of generators at Edison’s power plants. The young immigrant’s previous achievements had been promising. He had developed a model of an electric motor using rotating magnetic field without a commutator. Regrettably, in connection with the lack of effective alternating current generators, his achievement was not popularised at once and following his unsuccessful attempts at raising interest in his inventions among scientists and industrialists in Europe, Tesla aimed for the “land of great opportunities”.

 

Having completed the order of Edison Electric Light Company, Tesla offered the great Edison his services in the further improvement of efficiency of current generators by introducing alternating current but the “Wizard of Menlo Park” categorically rejected his offer and fired him without the promised payment. However, Tesla won the trust of other shareholders of EELC, including the famous John Pierpont Morgan and George Westinghouse, who supported the inventor in setting up a competitive business – Tesla Electric Light Company. In 1888 Tesla patented a two-phase induction alternating current motor.

 

 

In the following years the Serbian engineer spread his wings and his achievements in alternating current applications dwarfed the past achievements of Edison. The latter, exasperated, began a propaganda campaign, which nowadays would be termed “black PR”, publishing reports about risks connected with the use of alternating current and numerous deaths caused by AC. He even tried to coin the term “westinghousation” as a synonym of electrocution; however, his attempts were ineffective.

 

Tesla was a visionary type who, supported by Westinghouse, completed impressive projects which substantiated the advantages of alternating current. The first was the construction of the Ames hydroelectric generating plant located near Ophir in Colorado. In the summer of 1890 Westinghouse Electric supplied the station’s generator and motor and in the spring of 1891 a plant transmitting alternating current to the stamp mill at a gold mine 2.6 miles (4.2 km) away was put into service. The generator driven by a six-foot (2 m) Pelton wheel, had 100 horsepower and produced single-phase AC at 3 kV and 133 Hz. The transmission line was built from Western Union cross-arms with insulator carrying two bare copper wires. The total wire costs were about USD 700, about 1% of the cost estimated for a direct-current line, and it achieved a 95% transmission efficiency!

 

Another “nail in the coffin” for Edison was the demonstration of AC-supplied equipment during the World Fair in Chicago in 1893. Tesla presented a complete process cycle on specially prepared mock-ups but the spectators were most attracted by the illumination of the exhibition. More than 2000 bulbs supplied with AC illuminated more than 2.4  km2 of the surface covered by nearly two hundred new buildings, pavilions, artificial canals and bays, which were visited by more than 27 million people over six months (it is now estimated that this number corresponded to half of the US population at that time). Edison’s General Electric offered electric supply and illumination of the exhibition first for 1.8 billion dollars, then re-calculated the price and reduced it to 554 thousand, but the tender was won by Westinghouse offering 399 thousand dollars. In retaliation for his failure Edison banned Westinghouse Electric from using his bulbs, so a new type of electric source of light was quickly patented. It was created by Reginald Fessenden, who used iron and nickel alloy wires in his design instead of platinum used by Edison, thus he significantly reduced the cost of production and contributed to extending the service life of the lamp.

 

 

Perhaps the last element in support of alternating current was the construction of a power station on the Niagara Falls in order to supply current to the city of Buffalo 42 km away. Sceptics doubted whether the system was able to supply power sufficient for the needs of the city but Tesla was optimistic and stated that: “The Niagara could power the entire eastern United States”. It is not known how exaggerated this statement was but it is a fact that the project was a success – in 1896 Edward Dean Adams Power Plant, the world’s first large AC power station, was put into operation.

 

In Europe another event occurred which supported the use of alternating current: in 1888, a Polish engineer, Michał Doliwo-Dobrowolski, patented a three-phase electric motor. He carried out his works in Berlin with Allgemeine Elekiricitats Gesellschaft, previously known as Deutsche Edison Gesellschaft. Doliwo-Dobrowolski is considered the precursor of three-phase current usage. In the following years he successfully demonstrated its practical applications and put them into operation. He was granted more than 60 patents for his inventions and without excessive exaggeration the present common use of three-phase current can be attributed to him.