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For Power, Light and Railway Service - Direct
and Alternating Current—High

and Low Tension

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Copyrighted 1905
by the Derry-Collard Company.


In a very small, isolated plant, where a single generator is used, the current can be conveyed to the apparatus in which it is utilized in a comparatively crude manner; all, in fact, that is required being suitable conducting wires to complete electric circuit. If there are several generators, feeding into a more or less complicated network of distributing wires, the circuit connections will become complicated unless a systematic way of arranging them is resorted to. There will be considerable complication even if only one generator is used, providing the distributing system is complicated. To simplify the arrangement of the wiring, the best course of procedure is to run the wires leading from the generator, or generators, to a central point, and then from there branch out to the various distributing circuits. This central point to which the generator wires are run, and from which the circuit wires start, is called a switchboard. The general arrangement of a switchboard depends very largely upon the service it is to perform, and also upon the type of current it is to handle. For continuous currents we have the constant potential and the constant current systems, and each one requires a switchboard arranged in a decidedly different manner. For the alternating current systems we have the single phase and the polyphase, both being of the constant potential type. Constant current alternating currents are very seldom

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