Proceedings of the American Society of Civil Engineers Volume 32, PT. 2 (Paperback)

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. 1906 Excerpt: ...motors with much higher voltage than that used at present will probably be used extensively in the future, but they are not considered in the following. Three-phase induction motors may also continue to be used, but will not be considered here. Power Transmission. The motors receive the current through a transmission system from one or more central power-stations. The transmission system, where the source is a water-power central station feeding a long line, will consist of the high-tension lines; the transformers, located in stations along the line, for reducing the pressure; and the contact lines on the side of, or over, the center of the tracks, either with or without feeders. Where heat power-stations are used, they will be at favorable points along the line, where water and coal are cheap, at intervals varying with the amount and kind of traffic and type of machinery used. Where favorable sites for power-stations can be found at distances of from 40 to 60 miles, 20 000-volt, single-phase current can be produced directly at the dynamos and sent to the locomotives without transformation; or lower voltage and shorter distances may be used, especially where the traffic is large and consists of numerous units of moderate size. The use of the highest practicable voltage is especially desirable with very large but infrequent trains. As a very high and dangerous voltage must be used in the suspended conductor, it is essential to suspend it in such manner that it will never come down. Trolley wires sometimes break and falL Their method of suspension, therefore, is acknowledged to be inadequate. To prevent their falling, they are suspended from either one rope or wire immediately above, or from two ropes or wires in inclined planes. These carriers are of steel, ...