SWITCHBOARDS AND SWITCHBOARD APPLIANCES. 321 



sometimes installed in connection with a set of feeders as ex- 

 plained in Art. 150. 



A synchronous motor is generally provided with switches and 

 fuses, an ammeter, an exciter with its switches and rheostats, a 

 synchronizer, and an arrangement for starting. In some cases, 

 an auxiliary motor is used as a starter, and in other cases a 

 synchronous motor is started by inherent induction motor action 

 as explained on page 271, in which case a starting compensator 

 is used as explained on page 267. 



A synchronous converter is generally provided with the same 

 accessory apparatus as a synchronous motor with the addition of 

 a complete direct-current switchboard equipment. * 



A small induction motor is usually provided with a switch and 

 fuses. Large induction motors, however, are usually provided 

 with switches and fuses, ammeters, and starting compensators, as 

 described on page 267. 



Wattmeters are frequently installed in connection with alter- 

 nating-current generators in order that the station attendant may 

 have a knowledge of the relative power outputs of the several 

 generators. Sometimes watt-hour meters are installed in a gen- 

 erating station to record the total output of energy, and watt-hour 

 meters are frequently installed in connection with synchronous 

 motors, synchronous converters, and induction motors. 



148. Switchboards for generating stations. An alternating- 

 current generating station is usually equipped with a number of 

 alternators, and one or more direct-current exciters ; and such a 

 station generally delivers current to a number of feeder circuits. 

 Each alternating-current generator, each direct-current exciter, 

 and each pair of feeders must be provided with accessory devices, 

 as specified above, and it is the usual practice to group all of the 

 accessory devices belonging to one machine, or to one pair of 

 feeders, on one switchboard panel. Thus, we have what are 

 called generator panels, exciter panels, z.n& feeder panels. 



When a station is equipped with several alternating-current 



*See pages 184-199 of the first volume of this text. 



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