PRACTICAL OPERATION OF DYNAMOS. 



189 



ammeter is arranged to indicate the current delivered to each 

 pair of feeders. In the diagram of connections in Fig. 116 each 

 ammeter is shown as a millivoltmeter connected to a shunt, and 

 an arrangement is provided whereby each millivoltmeter can be 

 connected across the bus bars in series with a high resistance so 

 as to serve as a voltmeter. The four short lines at the bottom 

 of the diagram of connections in Fig. 1 16 are the feeders. 



Fig. 1 1 7 is a front view of a complete switch-board, of the 

 General Electric Company's design, consisting of two generator 

 panels and two feeder panels, and Fig. 1 1 8 is a back view of the 



bus bar 



bus bar 



H 



bus bar 



bus bar 



f bus bar 



Fig. 115. 



T bus bar 



same. The large horizontal bars shown near the top in Fig. 1 1 8 

 are the bus bars. The details of one of the generator panels 

 (except the circuit breaker at the top) are given in Fig. 119, 

 which shows a front, back, and side elevation of the panel and a 

 diagram of the connections. This panel is shown without a volt- 

 meter, and the " potential buses" are simply voltmeter leads 

 running along back of the switch-board, so that a single volt- 

 meter placed anywhere on the board may be connected through 

 these " potential buses " to any machine, or to any pair of feed- 

 ers, at will, by means of a plug switch which is pushed into the 

 " receptacle." Fig. 1 19 shows a pair of fuses instead of a circuit 

 breaker for protecting the generator. The ammeter is shown in 



