. The Bell System technical journal . winds, referredto above, is also given in Appendix II. With these two equationsit is possible to determine the expected natural wind threshold velocitiesof a wire arrangement through the use of the accelerated method oftest. An equation (7) for this use, which was obtained from theabove two equations (5) and (6), is also given in Appendix II. While empirical equations were developed only for the case of a TELEPHONE LINE WIRE SPACING PROBLEMS 221 pair of wires with equal sags, the appHcability of the acceleratedmethod is not limited to this case. It was als
. The Bell System technical journal . winds, referredto above, is also given in Appendix II. With these two equationsit is possible to determine the expected natural wind threshold velocitiesof a wire arrangement through the use of the accelerated method oftest. An equation (7) for this use, which was obtained from theabove two equations (5) and (6), is also given in Appendix II. While empirical equations were developed only for the case of a TELEPHONE LINE WIRE SPACING PROBLEMS 221 pair of wires with equal sags, the appHcability of the acceleratedmethod is not limited to this case. It was also used where the sagsin the two wires of a pair were unequal and, as referred to later, fordetermining the most promising design of insulating disc (describedbelow) for use in natural wind tests as a means of mitigating thecontacting on pairs with the wires spaced, 3, 4 and 6 inches. Anti-Contacting Insulators As stated above it was found that wires spaced 3 or 4 inches con-tacted in wind velocities rather commonly experienced. Some. Fig. 14—Insulating disc. contacting was also recorded on pairs with wires spaced 6 giving consideration to means of increasing the natural windthreshold velocities of such circuits to those occurring less frequently,two types of anti-contacting insulators were developed. One type,Fig. 14, was a perforated disc of insulating material. When this typewas installed on one wire of a pair it was not in contact with the otherwire of the pair except when forced there by the action of the wiresin wind. The other type. Fig. 15, was a rod-shaped insulating spacer bridged the two wires of a pair in the span. The insulating discs used were 3 and 4 inches in diameter. Thearrangements of these discs tested in natural wdnds comprised one,two or three discs per span per pair of w^ires. When one disc wasused, it was placed at the approximate center of the span on the wire 222 BELL SYSTEM TECHNICAL JOURNAL of the pair to the windward side of t
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