File:Bell telephone magazine (1922) (14754361414).jpg

Identifier: belltelephonemag19amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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heir attachments to thepole. Crossarms and poles may alsofail due to unbalanced loads on thepole structure resulting from breakageof the wire by excessive ice loads. The most serious condition, how-ever, from the standpoint of the poleplant, occurs where a strong windtransverse to the line either accom-panies the formation of ice and snowdeposits or follows a storm before theice accumulation has had an oppor-tunity to melt. A pole break due tosuch conditions is shown in Figure 10.It is fortunate, however, that whileice storms may occur fairly fre-quently and high winds still oftener,the chances of heavy ice and highwind occurring simultaneously arefairly remote. To investigate the effects of windon wires, considerable use is made ofthe wind tunnel, where conditions ap-proximating those encountered in ac-tual practice can be produced at will.Tests made both in the wind tunneland under natural conditions havedemonstrated the interesting fact that i9^0 Outwitting Open Wires Worst Foe 241
Text Appearing After Image:
Fig. 10. POLE DOWNThis pole has succumbed to the combined forces of ice-weight and wind when a line carries a number of icecoated wires, some of the wires offeran appreciable amount of wind shield-ing to other wires on the line. Inareas where ice is a factor, and inthose cases where the poles carry asufficiently large group of wires tofurnish effective shielding, allowanceis made for such shielding in theamount of strength provided in thepole structure. It might be noted inthis connection that while the effectof shielding on a group of wires issuch, in the aggregate, that recogni-tion can be given it in the pole design,no account can ordinarily be taken ofit in considering the effects of windand ice on individual wires. It is an entirely practicable matterto design both the wire and pole plantto withstand specified amounts of iceand wind, but it is not feasible, except in a general way, to design againstthe widely variable loads and condi-tions imposed by trees broken or up-rooted by

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