Download book The History and Progress of the Electric Telegraph; With Descriptions of Some of the Apparatus

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Download book The History and Progress of the Electric Telegraph; With Descriptions of Some of the Apparatus

The History and Progress of the Electric Telegraph; With Descriptions of Some of the Apparatus by Robert Sabine

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Author: Robert Sabine
Number of Pages: 76 pages
Published Date: 01 Mar 2012
Publisher: Rarebooksclub.com
Publication Country: Miami Fl, United States
Language: English
ISBN: 9781130000702
File Name: The.History.and.Progress.of.the.Electric.Telegraph;.With.Descriptions.of.Some.of.the.Apparatus.pdf
Download Link: The History and Progress of the Electric Telegraph; With Descriptions of Some of the Apparatus
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1869 Excerpt: ...that of induction currents offers many advantages; the line batteries are opened, and spaces between the signals are given by reversed circuits, which always work cleaner than those given by making and breaking the same current. The polarised relay above described is also profitably employed on lines worked only with galvanic currents, with which it is found to be far more delicate than the relays with springs. It is, however, necessary to give the armature o (Fig. 37) a bias on the side D', which is done by advancing the soft-iron continuation of the pole, N', of the electro-magnet a little nearer to the armature than N, by which, when no current passes, the tongue is held against the insulated contact, and the distances may be so finely adjusted that a very weak current suffices to move it. 93. The Magneto-Induction Key.--Instead of the Morse key, induction coil, and local battery, Siemens and Halske use also an instrument arranged in the form of a key, by which a coil of wire, wound on a soft-iron armature, is oscillated between the poles of a permanent magnet, and develops alternate currents for working the polarised relay. The magneto-induction key is shown in Fig. 64, in perspective. s and N are two rows of permanent bar-magnets; the upper ones with their north ends, and the lower ones with their south ends, in contact with a stout plate, P, of soft iron, which acts as a neutral block for all the magnets forming the battery. Between the poles of this system, and oscillated in an angle of a few degrees by means of a handle, H, in the frame between two screw points, is the soft-iron armature, as long as the magnet system is wide, cut in deep longitudinal grooves on opposite sides, as is shown by the sectional sketch, Fig. 65. In these grooves the coil, ...

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