Electrical instruments and telephones of the U.S. Signal corps (1911) (14776423923)

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

Text Appearing Before Image:

but owing to the size of the iron frame necessary to providefor an increased amount of equipment, it is erected apart from theswitchboard, usually close by, in a position where it will not interferewith the operation or enlargement of the switchboard, and so as tomeet all the other local requirements. An illustration of this typeof installation is shown in figure 04. CENTRAL ENERGY LAMP SUPERVISORY SWITCHBOARD. As stated previously, this type of switchboard varies from the onejust described principally in the fact that lamp supervisory signalsare provided for each cord. Another distinctive feature is that theline jacks are located immediately under the line signal5 with whichthey are associated: the latter, however, being more a detail of me-chanical construction than of the circuit, the signal and jack being 152 ELECTRICAL INSTEUMENTS U. S. SIGNAL COEPS. one removable unit. These switchboards are wired to operate nor-mally at 24 volts, but can be used on a 30-volt system by changing

Text Appearing After Image:

Fig. 04.—Main distributing or cross-connecting frame, Presidio of San Francisco. the lamp equipment to meet that voltage. The circuit of this switch-board is shown in fiure 95, ELECTRICAL INSTRUMENTS U. S. SIGNAL CORPS. 153 strip on jacks

electrical instruments and telephones of the u s signal corps 1911 book illustrations government printing office military united states army high resolution images from internet archive

1911

University of California

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public domain