. Operation of trains and station work; . Fig. 4. center of this is inserted a small piece of platinum;above this on the under side of the metallic lever isanother piece of platinum. The spring is arranged toseparate the two platinum points, thus opening the cir-cuit. A metallic arm or circuit closer is attached tothe base of the key near the second leg, so arrangedthat it can slide under the lip directly connected withthe first leg thus closing the circuit when the key isnot in use. To prevent the operator from receiving anelectrical shock the finger pieces of both the level andthe circuit cl
. Operation of trains and station work; . Fig. 4. center of this is inserted a small piece of platinum;above this on the under side of the metallic lever isanother piece of platinum. The spring is arranged toseparate the two platinum points, thus opening the cir-cuit. A metallic arm or circuit closer is attached tothe base of the key near the second leg, so arrangedthat it can slide under the lip directly connected withthe first leg thus closing the circuit when the key isnot in use. To prevent the operator from receiving anelectrical shock the finger pieces of both the level andthe circuit closer are of non-conducting material. TELEGRAPHY 27 THE RELAY. The chief use of the relay is to resist all over-produc-tion of current. It has its connections with both mainline and local circuits. It consists of an electro-magnethorizontally arranged upon wood and metallic base; thesmall magnet wires go through the base and connectdirectly with the main line binding posts. In front ofthe electro-magnet a metallic armature with a platinum. Fig. 5. point in its lever (connected by a fine wire runningthrough the base to one local binding post) is perpendicu-larly arranged freely by the action of the electriccurrent produced in the magnets, which strikes againsta platinum point arranged in the adjusting screw, inthe yoke or frame (which is also connected by a finewire running to the other local binding post) whichcloses the local circuit through the sounder, which alsohas its connection with the local binding posts and thebattery. One other adjusting screw in the yoke or 28 TELEGRAPHY frame with an insulated point, governs the play of thelevers from the magnets. An adjusting spring is at-tached to the armature and its purpose is to draw thelever away from the magnets when the magnets arede-magnetized.
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Keywords: ., booka, bookcentury1900, bookdecade1900, booksubjectrailroadtrains
