File:Electrical instruments and telephones of the U.S. Signal corps (1911) (14569828020).jpg

Identifier: electricalinstru00unitrich (find matches)
Title: Electrical instruments and telephones of the U.S. Signal corps
Year: 1911 (1910s)
Authors: United States. Army. Signal Corps
Subjects: Military telegraph -- United States Military telephone -- United States
Publisher: Washington, Govt. print. off.
Contributing Library: University of California Libraries
Digitizing Sponsor: MSN

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be used to illuminate the office, as the opposingE M F, of the one-storage cell (fig. 16) will not perceptibly diminishtheir light. As will be noted, the storage cell is constantly in use even while charging. On account of its low internal resistance, as many sounder circuitsin parallel can be fed from one of these storage cells as the capacityof the battery will permit. Each sounder requires one-fourth ampere, 52 ELECTRICAL INSTRUMENTS U. S. SIGNAL CORPS. SO in twenty-four hours it Avould require at most G aniphere hours tosupi)ly it. And if the storage cell had a cajiacity of 50 ampere hoursit could supply four sounder circuits twenty-four hours and still havea reserve for another day in case of accident to the charging circuit. The method of tapping off various voltages from a number ofstorage cells in series for the different lines is shown under the head-iuff of switchboard diagrams.
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ri(i. 17.—Tyijical battery iustalhilinii. Telephone hatteries.—As stated previously, telephone batteries atcoast artillery posts consist of 15 cells, and at interior posts of 12cells. These vary in size from ET to E-11 Chloride batteries ortheir equivalents. Fire-control telephone installations at coast-artil-lery posts are designed to operate at 30 volts, and the post-telephonesystems derive their current from the same source, leads being runfrom the switchboard rooms to the headquarters building, in which(he telephone switchboards are usually located. These telephone ELECTBICAL INSTRUMENTS U. S. SIGNAL CORPS. 53 batteries are usually installed in glass jars on a suitable rack, andfigure 17 illustrates an installation of this type. The size installedvaries with the requirements of each system. At interior posts thetelephone batteries are usually installed in the switchboard room atcentral and vary in size to fit the installation in question, E-5 beingthe largest, and in most case

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