Stationary steam engines, simple and compound; especially as adapted to electric lighting purposes . onomy byfurther increase becomes rapidly less with even the bestengines. The point of cut-off is calculated, in estimatesof power, to be at from one-fourth to one-fifth stroke, and,as a rule, nearer the first than the last figure. The bestratio of expansion for any given case is to be determined bya comparison of cost of fuel and steam supply with otheroperating expenses, at the place of operation. The engine above described has been used, in many cases,to supply power for driving dynamos in el
Stationary steam engines, simple and compound; especially as adapted to electric lighting purposes . onomy byfurther increase becomes rapidly less with even the bestengines. The point of cut-off is calculated, in estimatesof power, to be at from one-fourth to one-fifth stroke, and,as a rule, nearer the first than the last figure. The bestratio of expansion for any given case is to be determined bya comparison of cost of fuel and steam supply with otheroperating expenses, at the place of operation. The engine above described has been used, in many cases,to supply power for driving dynamos in electric lighting,and has an excellent record in that field, as well as in cotton 96 STEAM ENGINES FOR and flouring mills, which demand the most perfect possibleregulation. One of these engines (16x36), at the Cincinnati Exhi-bition of 1883, was tested by the committee on electriclighting apparatus and found to alter its speed but 2^2 percent., when the whole load, 124 horse-power, was thrown onor off; it varied one revolution per minute with a changeof steam pressure of from 90 down to 50 The indicator cards, of which copies are given aboveas taken from this engine, show the method of distribution ofsteam in engines with positive motion valve-gears, such asare here considered as fitted for direct connection withlarge dynamos, and for high speed generally. The illustra-tion exhibits a series of indicator diagrams taken from thisengine at points of cut-off varying from one-tenth to one-third stroke. It is seen that the steam lines are as straightas those of a drop cut-off engine, very nearly up to the pointat which the effect of closing the cut-off valve begins to ex-hibit itself in the production of the expansion line. The ELECTRIC LIGHTING PL A N TS. 9 7 expansion curve is very nearly that obtained by laying downthe hyperbolic curve of Marriotte, and the exhaust is asclean and prompt as need be desired ; the back-pressureline closely follows the atmospheric line seen im
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectsteamen, bookyear1890
