Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 373
a rectifier installed at the central office, the voltmeter should read upto 120 volts. An ammeter with center zero is also installed. Circuits, to beexplained later on, will show the ammeter so connected that when thecharging machine is in operation it will show the net amount of currentwhich the… … Fig. 281.—Solenoid ringingcurrent interrupter. POWER PLANT, SUPERVISORY AND TESTING EQUIPMENT 349 charging machine is in operation the current delivered by it may bemeasured. Instrument switches are used for switching the Volt and ammeters inconnection with the various circuits. The hand wheels of…
Telephone
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