A ROMANTIC STORY

Taranaki Daily News, 27 November 1926, Page 8

A ROMANTIC STORY

DISCOVERY OF ELECTRICITY. INSPIRATION OF THE PAST. The study of history must always be a matter of vital interest. Whether it be in tracing the social progress of the human race since the earliest civilisation, in following the development of a. particular nation through calamities and triumphs, or in studying the unfolding of some branch of art or science, there is a peculiar fascination in the subject. No more romantic story can be conceived that the history of the development and application of electricity in the service of man. If any one event can be regarded as the birth of electrical engineering, it is surely the discovery by Faraday in 1821 of the principle of the electric motor—that is, that a conductor carrying a current in a magnetic field experiences a force tending to move it. It is noteworthy that ten years elapsed before Faraday discovered magneto-electric induction, that is. the principle of the dynamo. Four years later Sturgeon invented the commutator, and in 1845 Cooke and Wheatstone used electro magnets instead of permanent magnets. It was during the years 1865-1873 that the shunt and series self-excited dynamo was finally evolved. Thus, step by step, were the primary principles of dynamo electric machines brought to light, and thus also were made possible the innumerable present day applications of electricity for power purposes. The development of incandescent lamps was similarly slow. The earliest attempts were made in 1841 with lamps having spiral platinum filaments: but it was not until 1878 that the commercial development of the incandescent lamp, was begun by Edison and Swan. The carbon filament lamp, the earliest form achieving commercial success, held its own for about twenty- years, but its displacement began with the osmium lamp. This was followed later by tantalum and tungsten filament lamps, working up to the present gasfilled types. The realisation of the idea of sunplying electric current from a power station for lighting houses in the vicinity owes much to the energy and business ability of Edison. In 1882 he installed two 90 k.w. 110-volt bi-polar steam-driven generators at Holbom \ induct. London, thus establishing the first central station. Ferranti was apparently the first to suggest that a power station should be situated outside the city supplied, at a pont convenient for fuel and water, and that the power should be transmitted by high voltage alternating currents. In 1890 lie built the Depford Station for the London Electric Supply Co., installing 10.000 volt alternators of 100 k.w. capacity each, and transmitting by underground cables. ' The pioneer overhead high tension line was built in 1891. and transmitted power at 8500 volts, three phase, over a distance of 110 miles from Lauffen to Fraiikfort in Germany. These achievements, wonderful in themselves, laid the foundation for the truly amazing advances that have been made in the last ten or twelve years. In 1913 the largest 3000 r.p.m. turbo alternators had a capacity of 7500 k.w. To-day such machines are built for 30.000 k.w., while 1500 r.p.m. machines are built up to 60,000 k.w. capacity, or five times the capacity of the original Lake Coleridge power-house, in a single machine. Turbine efficiencies have advanced, with increase in size and refinements in design from 14.5 per cent, in 1903 to 30.5 per cent, in 1924, while overall steam plant efficiencies have been brought up from 9.2 per cent, to 21.7 per cent. In the many other directions in which electrical energy is applied, progress has been just as remarkable to such an extent that one hardly dare speculate as to what the future will bring forth. Development in electrical engineering is almost a measure of general human progress. Such a state of affairs has arisen during the past century, that the task of carrying humanity along the road of progress has fallen increasingly to the scientist and the engineer. The fact must not be lost sight of, however, that every invention that has resulted in the .advancement of science and industry, has been the result of strenuous toil and painstaking research, no less laborious and creditable in this age than that which enabled primitive man to win his way to the first stages of progress.