File:The Street railway journal (1908) (14759791312).jpg

Identifier: streetrailwayjo311908newy (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

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-ing 8, 10, 12 or 15 tons, or double-truck cars weighing 15, 20, 25, 30,35 or 40 tons. The flywheels enable braking tests to bemade, as well as motor tests. The form of friction brake which has been used in con-nection with locomotive testing plants has here been re-placed by electric brakes, consisting of standard G. E. 57motors mounted on and geared to the shafts between thesupporting wheels. These motors act as generators, thefields of all four being in series and separately excited. Febkuakv 15, iyo8.) STREET RAILWAY JOURNAL. 255 Their armatures, however, are connected in parallel to aresistance load. While this resistance load is variable, itis only varied to care for extreme changes which may bedesired, as a better regulation is obtained, within limits, byvarying the field of the exciting generator, this varying inturn the fields of the brake generators and their voltage.It may easily be seen that power to overcome wind re-sistance and resistance due to track grades mav be taken
Text Appearing After Image:
FIG. 3.- -TESTING PLANT WITH TEMPORARY RAILS IN POSITION OV CAR FOR RKCEPTIOX up by the braking ettect of these generators, at the sametime being entirely separate from the power used to over-come inertia, which is correctly stored in the flywheels askinetic energy as momentum is acquired, to be dissipatedin friction as the car slows down either through driftingor braking. At the same time, the entire tractive efYort isshown by the pull on the drawbar of the car under test. The arrangement of brake generators above describedperforms another important function, that of keeping allsupporting shafts rotating at similar speeds at all times.The electric car is not commonly provided with connectingrods between drivers, conse(;uentlv some corresponding de-vice must be used between the supporting wheels, else thevarious car wheels would be running at \arious speeds ontest; especially would this be true while the car motorswere in a series connection. The series connection of brakegenerator fi

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