File:Bell telephone magazine (1922) (14570052529).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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lators. It is not alone the weight of ice ona wire which makes for damage. Itspresence also increases the sail areawhich the wire presents to the wind.The diameters of line wires commonlyused in telephone work vary fromabout .080 inch to about .165 inchand it is readily evident that a ^-inchradial ice coating increases the areaexposed to the wind by 700 to 1300per cent. With a sufficiently strongwind transverse to the line, the windpressure per foot of ice-covered wiremay considerably exceed the weightof wire and ice combined. For thisreason a heavy ice load acting to-gether with a strong wind results ina particularly destructive combina-tion. Moderate ice loads alone have littlemechanical effect on telephone wire.But fairly light glazes of ice whenacted upon by wind of only mediumintensity sometimes are responsiblefor a phenomenon known as dancing,which is now being given active studyon wires and cables both in serviceand at the Bell Telephone Labora-tories testing ground at Chester.
Text Appearing After Image:
Fig. 9. Cross-arms Down The weight of the ice load on these wires has pulled the cross-arms from the pole Dancing wires oscillate in a planevertical to the wind. The dancing issometimes of sufficient violence toshort-circuit the wires; to cause me-chanical damage at the insulators, dueto chafing; or to produce breakage orweakening of the wire from the fa-tigue of the metal which results whenthe wires are bent back and forthwhile dancing. Some types of longdistance carrier telephone circuitsmust be built with relatively closespacing between the two wires consti-tuting each pair, and on such circuitsthe swinging of ice-glazed wires in thewind may result in the actual freezingtogether of the wires. 240 Bell Telephone Quarterly OCTOBER Heavy ice loads or combinations ofice and wind may result in either wirebreaks due to the increased tensionsdeveloped or in permanent stretchingof the wire. Increased sags due topermanent stretching not only reduceclearances between wire and groundbut also

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