Hawkins electrical guide ... : questions, answers & illustrations : a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications ; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833-1928 · New York : T. Audel & Co. · leaf 146
l be no flow of current on the main line,but the current in the artificial line, flowing from the groundto the negative poles of the batteries will produce the magneticcondition required to close relay PR at station B while therelay PR remains closed by the action of the key K, thusfulfilling the… … I ^m i p i:-:f! Fig. 3,087.—Foote, Pierson walking beam type pole changer or circuit breaking reverser foruse with dynamo currents. The Bridge Duplex System.—This method is based onthe principle of the Christie or so called Wheatstone bridge*.It is used in the operation of submarine telegraph…
Electrical engineering
Internet Archive · Brigham Young University · Public Domain Mark 1.0. Free to use for anything.
![An illustration from The Telegrapher [microform] (1864)](https://img.insideoutlibrary.com/img/200/ia-telegrapher05nati-104-57.webp)
