. American engineer and railroad journal . lines, where they inter-sect the circumference at the points ce c and i b b. Make Fat the center line and the top and bottom of circle equal thetotal acceleration required divided by the ratio of main rod tocrank. Find a radius that will intersect the three points thus found, aud use it, instead of the straight line D 0, fig. 11,from which to measure the ordinates. The force required for reciprocation at any point of thestroke can be accurately determined, and the disturbing influ-ence caused by a mainrod of some given length, by the con-struction of
. American engineer and railroad journal . lines, where they inter-sect the circumference at the points ce c and i b b. Make Fat the center line and the top and bottom of circle equal thetotal acceleration required divided by the ratio of main rod tocrank. Find a radius that will intersect the three points thus found, aud use it, instead of the straight line D 0, fig. 11,from which to measure the ordinates. The force required for reciprocation at any point of thestroke can be accurately determined, and the disturbing influ-ence caused by a mainrod of some given length, by the con-struction of a diagram similar to fig. 1:5. The ordinates justfound in fig. 12 are measured off and plotted on correspond-ing vertical lines in fig. 13. These points when joined willproduce parabolas A B and CD. Having considered the manner of constructing the diagramsrepresenting the force absorbed or given out at different pointsof the stroke, it will be necessary now to show their relationto the indicator diagram, under different conditions, weight. Fig, 15 of reciprocating parts, and speed.£ Fig. 14 shows an indicatordiagram taken from the same class of engine previously usedits illustrating the vertical effect of counterbalance on thetrack. Speed, 60 miles per hour ; boiler pressure, 160 lbs.;cut-off, 8 in., or one-third of stroke ; length of main rod, 85-jj upper dotted lines represent the uncorrected card as itleaves the indicator. Weight of reciprocating parts, 589 lbs.,which are the actual weights now in service on the engine. In order to obtain a clear understanding of the diagram, itis first necessary to imagine the indicator card as it really ex-ists and not as it is usually shown, in which each card forfront or back ends of cylinder represents the varying pressurefor that end and not the actual thrust on the piston, which isthe steam line of one end, combined with the exhaust and backpressure of the other, as shown in fig. 15. A diagram of this 1NOICATOH OUC«UMS BASfD
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
