File:Electrical instruments and telephones of the U.S. Signal corps (1911) (14569890738).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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GNAL CORPS. 89 electro-magnet—that is. at its neutral point, namely, at the middleof the cores—any such effect is not perceived in practice. The play of armature of the Western Union polarized relay isadjusted by means of the small screw /S. Its position between thecores of the electro-magnet is regulated by the position of the frontand back contact points c, c. These contacts ride in a carriagewhich is movable, within certain limits, in the cylinder /?. The carriage is movable back and forth by the screw II. Thearmature may be placed directly in the center between the twopoles of the electro-magnet by the movement of the screw II. Thecores of the relay may be independently moved to and from the arma-ture by the screws N N. A form of polarized relay, a modification of what is known inEurope as the Stroh relay, now the standard of the Western UnionCompany, is shown in side view, figure 51. Its chief working partsare inclosed in a brass case with an ebonite top, in which there is an
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opening through which the armature lever comes. There is also asmall opening in the sides of the brass case through which the polepieces of the electro-magnets can be observed for purposes of ad-justment. In the figure this opening is enlarged in order to showmore clearly the relative positions of the coils E E., pole pieces, etc.In this relay an ordinary horseshoe magnet is employed as the per-manent magnet. It lies horizontally under the base B of the relayas outlined in figure 51, which is a side view of the relay. The relayhas two electro-magnets with separate cores. In this form the elec-tro-magnets lie horizontally, lengthwise, with pole pieces facing, andthe armatures are vertical, lengthwise, the lower ends of the armaturesbeing loosely inserted in a recess in short iron extensions from therespective ends of the permanent magnet by which the armatures areinductively magnetized. The pole pieces extend across the ends ofthe coils, but are connected to the cores as indicated. The

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