Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. . LOiVER CROSS-ARMFig. 22. Transposition Diagram of Ten Two-Wire Circuits to Reduce Mutual-Inductance then be in the direction of the arrows shown and the effects on thecircuit AB will be neutralized, provided the transposition, as thecrossing of the conductors is called, is made at the mid
Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. . LOiVER CROSS-ARMFig. 22. Transposition Diagram of Ten Two-Wire Circuits to Reduce Mutual-Inductance then be in the direction of the arrows shown and the effects on thecircuit AB will be neutralized, provided the transposition, as thecrossing of the conductors is called, is made at the middle of theline. Such transpositions are made at frequent intervals on trans-mission lines in order to do away with the effects of mutual-inductancewhich, at times, might be considerable. When several circuitsare run on the same pole line, these transpositions must be madein such a manner that each circuit is transposed in its relation to 44 POWER TRANSMISSION 35 the other circuits. The transposition of the circuits of a line com-posed of ten two-wire circuits is shown in Fig. 22. In the three-phase circuits, it is customary to transpose the threewires in order to do away with the effects of mutual-induction. Fig. 23. Transposition Diagram of Three Parallel Three-Phase Linesto Reduce Mutual-Inductance and in these transpositions the relative location of the wires is changedso as to bring each conductor the same average distance from everyother parallel conductor. Fig. 23 shows the way in which the con-ductors of three parallel three-phase lines may be transposed so asto do away with disturbances due to mutual induction. The lengthof the straight section varies in practice from about one-half mileto five miles. ALTBRNATINQCURRENT LINES Calculations. In dealing with alternating currents, Ohmslaw can be applied only when all of the effects of inductance andcapacity have been eliminated and, since this can seldom be accom-plished, a new formula must be used which takes such capacity
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