SWITCHBOARDS AND SWITCHBOARD APPLIANCES. 327 



regulator (see Art. 150) are indicated, the regulator being operated 

 by the hand wheel shown on the front of the switchboard. 



An alternating-current three-phase feeder panel (A.T.F. panel) 

 and its diagram of connections are shown in Fig. 278. In this 



. n 



Not furnished w/tfi 

 Pane/ 



Back View 



Fig. 278. 



case, the main switch is a three-phase single-throw automatic oil 

 switch so arranged that an excess of current in either one of two 

 of the feeder wires may trip the switch. 



Figure 279 is a front view of a three-phase switchboard con- 

 sisting of two generator panels, and two three-phase feeder panels. 

 A synchronism indicator of the dial form is shown mounted on a 

 bracket at one side of the board. In this switchboard the exciter 

 accessories (rheostat and field switch) are mounted on the gen- 

 erator panels. 



