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 346
tage relays, which start the motor-generator whenever thepressure falls to 46 volts and which stop it when it reaches 52 volts. Aself-closing reverse current circuit breaker stands between the generatorand the battery. When the generator voltage is high enough to be safe,the circuit breaker closes… … Fig. 273.—Community automatic exchange 100-line (back). The power board circuits are shown in Fig. 274. The counter-cellswitch consists of a heavy copper arm mounted on a shaft which rotatesso that one end of the arm passes over a semicircular row of contacts.These are of heavy construction and…
Telephone
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