. The Street railway journal . hedule speeds. The moreonerous conditions imposed on the electric apparatus to meet theever increasing demand for larger and heavier equipments, and thedemand for greater seating capacity on systems already operatingat 500 to 550 volts, has led to an increase in the generated have been accustomed to consider 500 to 550 as the standarddirect-current voltage, but 600 volts is now being used to such anextent that it has really become the standard for the power role of the manufacturer is to design and construct such appa-ratus as will best mee
. The Street railway journal . hedule speeds. The moreonerous conditions imposed on the electric apparatus to meet theever increasing demand for larger and heavier equipments, and thedemand for greater seating capacity on systems already operatingat 500 to 550 volts, has led to an increase in the generated have been accustomed to consider 500 to 550 as the standarddirect-current voltage, but 600 volts is now being used to such anextent that it has really become the standard for the power role of the manufacturer is to design and construct such appa-ratus as will best meet the conditions of the operating companies,and it is, therefore, the requirements of the operator that shouldbe studied rather than the development of any particularly idea. The direct-current railway motor has been greatly improved, andhas undergone more changes in detail than is perhaps generallyappreciated. The old troubles of sparking and flashing at the com-mutator have been practically eliminated. Previously it was con-. 400 SOO 600 700 800 900 700 ieoo mo zooo swo FIG. 1.—PERFORMANCES OF A 2000-KW CURTIS TURBINE ATDIFFERENT LOADS AND UNDER VARIOUS STEAMCONDITIONS sidered advantageous to short circuit a turn on the field winding toreduce the sparking at the brushes and in the controller, the ideabeing to restrain the rapidity with which the magnetism of themotor changed, but several years ago it was found that while thisprovision decreased whatever troubles occurred, due to opening thecircuit, it was a positive cause of Hashing in case the current wasinterrupted and suddenly applied. For example this trouble wouldoccur on passing a section insulator with the controller on, andmore especially when operating with sleet on the trolley wire orrunning over a third rail with an uneven surface. The field coils as now made not only have no short circuitingturns, but where metal spools are used, it is customary to split thespool and introduce an insulation into the shell to eli
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
