. Electrical news and engineering. rs back into place and started back to-wards the tower only to discover that the grade in the cablewas so great that they could not pull themselves uj). Theysolved the difficulty by looping the tackle line that they hadwith them over the steel cable and sliding down the feetto a boat waiting below. A short time later an insulator onone of the other lines broke loose and it was similarly re-connected. This time, however, we profited by our formerperience and provided a tail line l)y means of wliich theriggers were pulled back to the tower. Since then we h
. Electrical news and engineering. rs back into place and started back to-wards the tower only to discover that the grade in the cablewas so great that they could not pull themselves uj). Theysolved the difficulty by looping the tackle line that they hadwith them over the steel cable and sliding down the feetto a boat waiting below. A short time later an insulator onone of the other lines broke loose and it was similarly re-connected. This time, however, we profited by our formerperience and provided a tail line l)y means of wliich theriggers were pulled back to the tower. Since then we haveexperienced no trouble from this source. The cables, as originally strung, allowed the followingclearances betw-een the copper conductors and the averagewater level during the season of navigation: Down stream ; ft. Centre ft. Upstream ft. The temperature at time of erection was about 20 As there is a change in sag of approximately one each 10 deg. change in tempcratuure tft above would cor-. Cable test —Sample of cablewith grips attaclied. Elastic limit 158,500 pounds; ulti-mate strengtli pounds. respond roughly to clearances at 110 deg. fahr. of and ft. respectively. At the time these cables were erected we naturally ex-pected the sag to increase as the cables stretched under theload until the strands were drawn tightly together. Therewas no data available with to the amount of stretchto expect so that it was impossible to allow for this in sag- 34 THE ELECTRICAL NEWS December 1, 1918 ging the cables. The hoist, therefore, was left in positionso that we could pull up the cables when the sag becametoo great. In May of this year we found that the sag in the cableshad increased by from 24 to 27^ ft. and that in order toobtain the necessary clearance over the channel we wouldhave to take up 34 ft. in the sag of the down-stream cableand 13 and 14 ft. in that of the centre and upstream cablesrespectively.
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