. Journal of electricity, power, and gas . r determining velocities was ex-plained. The construction in Fig. II utilizes this prin-ciple. The point I is the instantaneous center aboutwhich the connecting rod is rotating. This is verifiedsince the two ends are each seen to be moving at right angles to the lines drawn to I and hence I must be thecenter for the instant pictured. The velocity of O was in our example found tobe 300 in. per second. Lay ofif a line perpendicularto the crank (or to Q I) 15 in. long and call this thevelocity of 300 in. per second; that is, each in. ofthis line represen
. Journal of electricity, power, and gas . r determining velocities was ex-plained. The construction in Fig. II utilizes this prin-ciple. The point I is the instantaneous center aboutwhich the connecting rod is rotating. This is verifiedsince the two ends are each seen to be moving at right angles to the lines drawn to I and hence I must be thecenter for the instant pictured. The velocity of O was in our example found tobe 300 in. per second. Lay ofif a line perpendicularto the crank (or to Q I) 15 in. long and call this thevelocity of 300 in. per second; that is, each in. ofthis line represents 20 in. per second of velocity. Con-nect the end of this line R with I and then drawthe line Vx parallel to Q R at the end of the arcfrom P. This Vx represents (to the same scale) thevelocity of the crosshead at that instant. If, now, the connecting rod line P Q be extendedtill it intersects the vertical line through O at S it willbe found by measurement (and can be proven truemathematically) that the line O S is equal in lengthto Vx. r. Hence by choosing our scale of crank linear veloc-ity numerically ecjual to the length of the crank thecrosshead velocity can be determined for any positionby simply extending the line of the connecting rodthrough to the vertical line from the shaft center. It will be seen that S will extend above the cir-cumference of the crank pin orbit when the connect-ing rod is tangent to this orbit and hence the crosshead velocity is at this point greater than the velocityof the crank pin Q. On the backward stroke S will be below the cen-ter line indicating the reversed direction of the cross-head velocity. These velocities may be laid out as perpendic-ulars from each position and will give the ellipticalfigure shown. Were the connecting rod very greatin comparison with the length of the crank this figurewould be an ellipse. The new Anglo-French telephone cable across theEnglish channel is equipped with Pupin or loadingcoils imbedded in the cores at eac
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Keywords: ., bookcentury1800, bookdecade1890, bookidjo, booksubjectelectricity
