Electrical Engineer's Pocket-Book; A Hand-Book of Useful Data for Electricians and Electrical Engineers...

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 Excerpt: ...danger points lias been proportionally increased, and with it the amount of electrolytic action or corrosion. Fig.S3. On the whole, the placing of the current positive to line appears to be a material advantage. Corrosive action is very much enhanced in a limited area, but being in a limited area and definitely located, it mav be easily watched and relnedies applied. With the current negative to line, the action at a given danger point may be considerably less than under the other condition; but as the danger district is widespread, and as the conditions are continually changing, it would be very difficult to locate precisely the danger points. Consequently the results of electrolytic action are likely to appear at unexpected points. From the electric railway standpoint, the prohibitive expense of the requisite addition of copper to make a complete circuit is advanced, together with the impracticability of a double-trolley system that is apparently a necessary concomitant of the metallic return; and these arguments have a certain weight. There is no question but that the complete metallic return is in the beginning a more expensive installation, but per contra few railway companies have any idea of the energy now expended in returning the energy delivered by the power station through the poor conductivity of the average railway track with its surrounding earth. It has been suggested that corrosion from the underground current could be avoided by operating the railway as a three-wire system in which the trolley wires would form the two sides, and the ground play the part of a neutral wire. The feasibility of a three-wire system depends upon the ability to obtain a double track through the entire railway territory, and the adoption of such a car schedule as t...