. The Street railway journal . etweenpoints, with a minimum rate of $10. 792 STREET RAILWAY JOURNAL. [Vol. XXXL No. 19. ALUMINUM CELL LIGHTNING ARRESTER The General Electric Company has just placed on themarket a form of electrolytic lightning arrester known asthe aluminum cell arrester for operation on alternating-current circuits. It consists essentially of a series of con-centric inverted cones placed one above the other vi^ith avertical spacing of about 3/16 in. The cones are insulatedfrom each other except for the electrolyte which partiallyfills them. Each cell then consists of two alumi
. The Street railway journal . etweenpoints, with a minimum rate of $10. 792 STREET RAILWAY JOURNAL. [Vol. XXXL No. 19. ALUMINUM CELL LIGHTNING ARRESTER The General Electric Company has just placed on themarket a form of electrolytic lightning arrester known asthe aluminum cell arrester for operation on alternating-current circuits. It consists essentially of a series of con-centric inverted cones placed one above the other vi^ith avertical spacing of about 3/16 in. The cones are insulatedfrom each other except for the electrolyte which partiallyfills them. Each cell then consists of two aluminum conesand the intervening electrolyte. A sufficient number of cells placed in series form a com-plete arrester, the electrical characteristics of which arethe same as a single cell. The cones complete with theelectrolyte are immersed in a tank of oil which affords thenecessary insulation and great heat-absorbing tanks are made of welded steel and are equippedwith wooden covers and suitable porcelain ALUMINUM CELL LIGHTNING ARRESTER The efficacy of the cones as a lightning arrester dependsupon a thin film which is formed upon the surface of thealuminum by a special process of manufacture. This filmmay be compa/red with the safety valve of a steam boilerwhich opens at a definite pressure and allows the steam toescape. Each cell, that is, two adjacent cones with interveningelectrolyte, is designed to operate normally at 300 the potential rises to any value greater than 300 voltsand less than 420 volts, the film allows the discharge totake place, but a thicker film is immediately formed andthe current is again decreased to a small value. When theline potential becomes normal this extra thickness of filmgradually dissolves, leaving the film in its normal condition. At 420 volts (about 40 per cent above normal voltage)the film opens and allows a free and heavy discharge totake place. This voltage represents the maximum criticalfilm value per cell
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
