DO IT ELECTRICALLY

Dominion, Volume 21, Issue 118, 16 February 1928, Page 7

DO IT ELECTRICALLY

Motor’s Recuperative Powers. A particularly interesting example of the recuperative powers of electric motors is mentioned in an English electrical journal. A British 450 h.p. 4pole slip ring induction protected type motor, was completely immersed in pit water in a caol mine for eleven days, dried out without being brought to the surface, and put back into service. I drives a centrifugal pump, and is wound for 6000 volts, 40 cycles, threephase. During its immersion so much grease, coal dust, and mud were deposited that it was found necessary first to dismantle the motor in order to clear the coils, slots, and internal framework; drying out was done by reassembling, short circuiting the rotor, and passing a current of 22 amperes through the stator winding. This drying out occupied ten days, the current being passed for an eight-hour shift in every 24 hours, i.e., for a total time of 80 hours. Insulation tests were taken during each shift when a temperature of 160 degrees F. was registered 111 the windings. The machine has thoroughly impregnated former wound ’ coils in open slots, the insulation being of mica, put on by the Haefely process. Power in Steel Industry. During the last twenty years the use of electricity for the manufacture of steel has so advanced from an embryonic stage that there are now more than 1200 electric furnaces in operation in Europe and America (an exchange states). Of late years the developments of this application nave been such that the output of electrical steel was nearly doubled in the ten years following 1910, when it was 5.,141 tons, and has again doubled itself from 1920, until in 1925 we find that no fewer than 1,042,000 tons were produced by this method, Great Britain being responsible for 44,000 tons and the United States for 615,000 tons. Perhaps no less important than the production of steel are the possibilities of the non-ferrous groups. Single furnaces of 4000 to 10,000 k.w. capacity are now engaged in smelting pig iron and in making carbide, while probably about half a million kilowatts are employed in melting both ferrous and non-ferrous metals. One of the most important possible classes of consumers in this connection is undoubtedly that using smaller units applied to the melting and treatment of alloys of copper, nickel, zinc, and the precious metals, and it is surprising, therefore, that the electric furnace, which is so eminently suitable for the production of alloy,, should not be more widely used. Brewing Industry Becoming Electrified. That the brewing industry is rapidly becoming electrified was clearly evident from a visit to the recent Brewers’ Exhibition held in London at the Royal Agricultural Hall, states “Electrics.* While it was to be noted that there was no radical change in the de. sign of brewery machinery, it was interesting to observe that in all cases the exhibits demonstrated the application of the electric motor for driving the wide range of machinery used in tlie modern brewery. On one stand was to be seen the small fractional horse-power motor operating a labelling machine, while on others there were to be found mammoth bottle washing or cask cleaning machines driven by elec, trie power. In fact, the whole exhibition afforded an excellent example of tiie adaptability of the electric motor as a form of prime mover in the brewery.