. Electrical world. ngon the cross-section of ice-covered wire, the pressure per foot pounds. As this force acts at right angles to the weight, ^ pounds, which may be resultant force = +considered the maximum for Sd- For the catenary curve, L ^ L -{- Where L = actual length of cable,L ^= length of span,d =: central deflection. 3L 3L (I - L) Transposing, d = -22 ELECTRICAL WORLD and ENGINEER. Vol. XLIII, No. i6. From these two formulae, d can be figured for any temperature, theinitial sag being 35 ft. at 212° F. The following table gives the sagfor temperatures bet
. Electrical world. ngon the cross-section of ice-covered wire, the pressure per foot pounds. As this force acts at right angles to the weight, ^ pounds, which may be resultant force = +considered the maximum for Sd- For the catenary curve, L ^ L -{- Where L = actual length of cable,L ^= length of span,d =: central deflection. 3L 3L (I - L) Transposing, d = -22 ELECTRICAL WORLD and ENGINEER. Vol. XLIII, No. i6. From these two formulae, d can be figured for any temperature, theinitial sag being 35 ft. at 212° F. The following table gives the sagfor temperatures between 212° F. and minus 20° F.: Temp. F. Deflection Substituling in equation (l) the values,w := pounds (the maximum weight),d = ft. (minimum deflection),L := 1,000 ft. T (the maximum tension) X 4-318 X 29,400 pounds. The sectional area of cable is .8 sq. in., giving a tensilestrength of .8 X = 28,000 pounds per cable. Comparing. FIG. 3.—VIEW OF OXE TOWER .\ND THE LINE. this result with the tension, 29,400 pounds, it is seen thatthe line will not severe conditions as set down. To re-lieve the strain, the line should be lengthened in the fall, and. toprevent excessive sag, taken up again in the spring. Suppose a range of temperature from 60° F. to — 20° F. be takenfor the winter. Then the line could be allowed a drop of 35 ft. atthis maximum temperature, which by reference to the table, wouldmake the equivalent sag at — 20° F., ft. Substituting in formula (i). 1,000- X 4-31 T = ^^ lbs., 8 X or the one setting would give a safe tension on the cable for the con-ditions noted; though for severe conditions it would be well to givethe maximum drop of 35 ft., as the adjustment requires only a few-minutes work. As a summation, the maxiinum strain per cable is pounds,or per tower, 4 X 19,000 =: 76,000 pounds. The horizontal com-ponent due to the wi
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
