Seite - 50 - in Nikola Tesla and the Graz Tech

50 The electrical engineering industry of the USA played an important role in the construction of an economical and powerful electricity system at that time. One of the leading electrical engineering companies, the Westinghouse Company, along with its advisor Tesla, developed a functioning polyphase cur- rent system and introduced it to the market. Commercial success was initially hampered by the fact that a large number of industrial branches were already being supplied with DC, and large-scale DC power stations had been and were being built. This circumstance complicated and delayed the overall conversion to alternating current. Triggered off by the more than 40 patents which had been granted to Tesla up to 1891, an economic battle got under way between the proponents of the DC and AC systems. In particular, the Edison Company and the Thomson-Houston Electric Com- pany – both merged to form General Electric in 1892 – offered fierce resist- ance against alternating current in a one-sided, dirty propaganda war /3/. This occurred against their better judgment for Edison knew that only AC can be transformed and that electrical energy can only be transmitted over great distances using very high voltages at low loss. Tesla designed AC generators, AC motors and transformers for the Westing- house Company, which were mass produced and in 1891 also used in the mines of Colorado. Despite many years of bad press for AC, George Westinghouse and Nicola Tesla celebrated the final triumph over DC at the Chicago World Fair in 1893. There was a public comparison test to find out whether direct current or alternating current should be used to power the first all-electric world ex- hibition. This was impressively won by the Westinghouse Company due to the work of Tesla. Tesla introduced a two-phase induction motor with a capacity of some 220 kW while a generator produced electricity at the frequency of 30 Hz adapted to the motor. Another prestige project in the War of the Currents between direct current and alternating current was the use of the Niagara Falls for electricity gen- eration and supply to the city of Buffalo some 32 km away. After intensive discussions about the available technical solutions, those responsible decid- ed in favour of Tesla’s polyphase alternating current system. In October 1893, the Niagara Commission awarded the Westinghouse Company the contract to develop a hydro-electric power station to utilise the energy of Niagara Falls using the alternating current system.