. Electric railway journal . Groups in series are used at dead endsto take the strain of and to insulate the line wires. TheWestinghouse Form P-2 porcelain strain insulators shown inthe accompanying cut are made of a grade of porcelain said to be much superior tothat ordinarily used forsuch appliances. Theglaze is a dark brown,so the insulators do notreadily attract attentionin the air. Sharp cor-ners that would be apt tochip have been avoidedand the shape of the grooves is such that the wires lie naturallyin them. The break-down voltage when the insulators are dry isabout 20,000 volts for eac
. Electric railway journal . Groups in series are used at dead endsto take the strain of and to insulate the line wires. TheWestinghouse Form P-2 porcelain strain insulators shown inthe accompanying cut are made of a grade of porcelain said to be much superior tothat ordinarily used forsuch appliances. Theglaze is a dark brown,so the insulators do notreadily attract attentionin the air. Sharp cor-ners that would be apt tochip have been avoidedand the shape of the grooves is such that the wires lie naturallyin them. The break-down voltage when the insulators are dry isabout 20,000 volts for each of the three sizes. The approximateultimate tensile strengths of the insulators, when wired up inguy wires, are respectively 14,000 lb., 16,000 lb. and 23,000 if one of these insulators fails either because of excessivestress or through accident, the wires that it carries cannot dropbecause they are interlinked. Two of these insulators areoften installed in series; then if one breaks the other Porcelain Strain Insulators AIR-COOLED CHOKE COILS It is sometimes convenient to mount choke coils on ceilingsso that the insulating coil supports hang pendent. At othertimes it is preferable to arrange them so that the coil rests onthe supports, as shown in the accompanying cut of the newWestinghouse Dt coil. This coil can be mounted either way,because the insulating columns can be removed and inverted by taking out four aluminum rod, bentinto a helix of about 15in. diameter and contain-ing about thirty turns,forms the coil clamps are pro-vided to give mechanicalstrength to the aluminum rod usedis of sufficient diameterto carry 200 amp coil is supportedon two insulating col-umns made up of por-celain insulators, which,except for the end piecesare interchangeable. Thenumber of insulatorsused in any column de-pends on the voltage ofthe circuit in which thecoil is to be used. These coils can bemounted in any positi
Size: 2295px × 1089px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidelectricrailway371911newy
