CHAPTER XV. 

 SWITCHBOARDS AND SWITCHBOARD APPLIANCES. 



147. Recapitulation. The preceding chapters are devoted 

 chiefly to the discussion of individual machines such as the alter- 

 nator, the transformer, the induction motor, and the rotary con- 

 verter, and but little has been said of the combinations of 

 machines into complete systems for the generation, transmission 

 and utilization of power. This chapter refers to the general ar- 

 rangement of apparatus in generating and receiving stations and 

 Chapter XVI refers to the arrangement of transmission lines. 



Most of the details of arrangement in generating and receiving 

 stations refer to the accessory apparatus which must be used for 

 controlling and operating the various machines. Thus, a group 

 of alternating-current generators operating in parallel require the 

 following accessory apparatus : One or more exciters with their 

 field rheostats and switches, field regulators such as the Tirrill 

 regulator which is briefly described on page 14 and more fully 

 described in Art. 155, ammeters, voltmeters, potential and cur- 

 rent transformers (see pages 46 and 234), switches for opening 

 and closing the main circuits of the generators, and synchroniz- 

 ing devices (see page 155 and also Art. 151). Quick-acting cir- 

 cuit-breakers are preferably inserted in the various feeder circuits, 

 because a quick -acting circuit-breaker in the main circuit of a 

 generator throws the entire system out of operation in case of a 

 short circuit. 



A set of feeders, single-phase or polyphase, leading out from a 

 generating station to a certain locality is generally provided with 

 the following accessory apparatus in the generating station : 

 switches, circuit breakers or fuses, ammeters, ground detectors, 

 and lightning arresters.* A voltage regulator (and voltmeter) is 



* See pages 210-220 of the first volume of this text. 



320 



