. The Bell System technical journal . bout nine months and hasresulted in a higher quality of lead sheath due to more uniform compo-sition maintained. In addition there are considerable savings in fuel,reduction in dross, and elimination of a large amount of heavy manualeffort. The press room is now clean and cool, resulting in much betterworking conditions and in turn an indirect improvement in thequality of the product. LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 461 Testing Lead Covered CableAfter the cable is stranded each conductor is tested from end to endfor continuity and against ever
. The Bell System technical journal . bout nine months and hasresulted in a higher quality of lead sheath due to more uniform compo-sition maintained. In addition there are considerable savings in fuel,reduction in dross, and elimination of a large amount of heavy manualeffort. The press room is now clean and cool, resulting in much betterworking conditions and in turn an indirect improvement in thequality of the product. LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 461 Testing Lead Covered CableAfter the cable is stranded each conductor is tested from end to endfor continuity and against every other conductor for crosses. Defectsare repaired and after the cable core has been dried the lead sheath isapplied. After the application of the sheath the cable is allowed tostand until it cools to room temperature. Fig. 29 shows the coolingfloor and test mezzanine in the Point Breeze cable plant. The reels ofcable issue from the lead presses at the right; are cooled in the centralarea and tested beneath the mezzanine at the Fig. 29—^CooIing floor and test mezzanine. When the cables are cooled the conductors are given a final test foropens and crosses which may have developed due to strains imposedduring the sheathing process. Most toll cables have a number of sparewires and if fewer than the allowable number of above defects are foundthe cable is tested for dielectric strength, insulation resistance, mutualcapacitance, capacitance unbalance and defects in the sheath. Die-lectric strength tests are made between each conductor and every otheradjacent conductor to which failure may occur and between allconductors and the lead sheath. The potential used for these testsranges between 350 volts, , the lowest value used for certain con-ductor to conductor tests and as high as 5,000 volts, for someconductor to sheath tests. In making the conductor to conductortests a large number of circuits are involved so that interesting prob- 462 BELL SYSTEM TECHNICAL JOURNAL
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
