Electrical instruments and telephones of the U.S. Signal corps (1911) (14754206374)

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:
FiG. 98. -Fifty-drop. North Electric Compfiny mairnetoswitchboard. ELECTRICAL INSTRUMENTS U. S. SIGNAL CORPS. 159 nently connecting together the outside normal contacts, the key inquestion being designated as No. 94 in the cord circuit shown infigure 99. If power current should be available, it should be connected to thesprings marked generator, Nos. 1 and 2 on the terminal board ofthe switchboard and the key circuit retained in its present form. /4/7S Orange Green Call
Text Appearing After Image:
No ?0 Indcoil ^ 3-4 Trans ballery5-6 Night bell battery1-8 Telephone tap P^iver clipsQr lund Two No. 94 keys with red handles placed on leftside of key board. Fir.. 99.—Circuits of fifty-drop, Nortli Electric, magneto switctiboard. It has also been found in some cases that the generator armaturesof these switchboards continue to revolve after a call has been made,thus unscrewing the generator handle from the driving shaft. Toavoid this a high resistance will be provided to be bridged across con-tacts Nos. 2 and 3 of the hand generator shown on the circuits referredto above, in order to furnish a slight load for the generator and cause 160 ELECTRICAL INSTRUMENTS U. S. SIGNAL CORPS. the armature to stop as soon as the generator handle is released. Arefpiisition should be made for these resistances wherever their use isconsidered to be of advantage. OBSOLETE TYPES OF SWITCnBOARDS. To cover those types of switchboard now in more or less extendeduse,but no longer supplied, there are reta