. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . The motor may be of any standarddesign. Ringing Current.—Harmonic converters (pole changer sets) andmotor generators are used for ringing, one of the latter being shown at the POWER PLANT, SUPERVISORY AND TESTING EQUIPMENT 347 right of Fig. 279. The motor generator is usually equipped with sets ofsprings (seen in the view referred to above) designed to furnish the makeand break contacts for the generator control relays and to distributethe switchboard load in such a way that the generator will supply ring
. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . The motor may be of any standarddesign. Ringing Current.—Harmonic converters (pole changer sets) andmotor generators are used for ringing, one of the latter being shown at the POWER PLANT, SUPERVISORY AND TESTING EQUIPMENT 347 right of Fig. 279. The motor generator is usually equipped with sets ofsprings (seen in the view referred to above) designed to furnish the makeand break contacts for the generator control relays and to distributethe switchboard load in such a way that the generator will supply ringingcurrent to the various switchboard sections in succession, and not berequired to furnish the ringing current needed throughout the entireswitchboard at one time. In addition to the ringing springs these motorgenerator outfits carry busy, dial tone and howler attachments. Some-times the ringing machine used regularly is operated by the commercialpower circuit, while the reserve machine is a dynamotor driven from theexchange storage battery. With this arrangement, a failure of the. Fig. 280.—Power switchboard and charging machine. commercial source of power supply for a few hours will not disable thetelephone plant. The reserve ringing apparatus, in the plant in whichthe photograph reproduced in Fig. 279 was taken, is a harmonic-con-verter outfit; in fact, two harmonic-converter ringing outfits are installed,each consisting of a pole changer, a suitable transformer, for cycle ringing current, and a device for furnishing the interruptedbuzz, used as a busy signal. When harmonic converters are used it is customary to provide sole-noid ringing interrupters to feed interrupted ground to the generatorcontrol relays. Two of these interrupters are shown at the extremeupper right-hand side of the power board in Fig. 279. This ringing interrupter (Fig. 281) consists of a solenoid which, by :;is A UTOMA TIC TELEPIION Y means of its plunger, controls a rod carrying a p
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttelephone, bookyear19
