File:The Street railway journal (1901) (14735746466).jpg

Identifier: streetrailwayjo181901newy (find matches)
Title: The Street railway journal
Year: 1884 (1880s)
Authors:
Subjects: Street-railroads Electric railroads Transportation
Publisher: New York : McGraw Pub. Co.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
and en-gines, the power transmitted through the shafts and thetotal weight u))on the shafts are not the same in all thestations. The adoption of the moderate rotative speed of 75 r. ;). m.IS one of the evidences of safe conservatism which seemsto characterize the designs of all three stations. Corlissengines have run successfulh at 100 revolutions and u))-wa.rd, and piston and slide valves at much higher speeds,and higher speeds would greatly decrease the size andcost of engines and alternators for a given power, l)ut ithas seemed wise to the engineers intrusted with the de-si^gns to keep well within safe limits of speed in order toinsure greater durability of the valve mechanism andlessen the danger of breakdowns and the inconvenience ofstoppages for repairs. In the general design of a whole system of electricalgeneration and distribution for traction purposes the workof the electrical engineer may be said to begin at the thirdrail or underground conduit rail and lu proceed backward
Text Appearing After Image:
October 5, 1901.) STREET RAILWAY JOURNAL. 443 to the rotating part of the ahernator which is keyed tothe engine shaft. The design of the steam engineer beginsat the shaft, which is to turn a given number of revolu-tions per minute, which is to transmit a given horse-power to the alternator, and which is to be of such pro-portions that it will not appreciably deflect under the loadit carries, and proceeds backward to the coal pile. Thesize of the combined unit of alternator and engine may belimited by the state of the art of engine building and arma-ture building. It is also limited by the facts that thestation as a whole has to be designed with reference tofluctuating loads, the total power during the period ofpeak of the load being ten or more times as great asthat required during four or five hours after midnight, thatone or more units may at any time be out of service forrepairs, and that the efficiency of alternators decreases withlight loads, while that of engines decreases both

Note About Images