CURRENT-LIMITING REACTORS 



479 



been designed by which the results can be obtained directly and 

 with sufficient accuracy for most practical purposes. 



It consists of a table under which are mounted a number of 

 rheostats of the disk type having the operating handles pro- 

 jecting through the top of the table as shown in Fig. 296. To 

 each handle is fastened a pointer which revolves over a graduated 

 dial on top of the table, the graduations being in per cent reac- 

 tance (actually resistance). The terminals of each of the rheo- 

 stats are brought out to metal blocks, also fastened to the top of 

 the table. These blocks contain holes in which may be inserted 





FIG. 296. Device for Calculating Short-circuit Currents. 



taper plugs connected together by flexible leads so that the rheo- 

 stats can be interconnected in any desired manner. The resistance 

 of the rheostats is taken as representing reactance in an actual 

 system, and a rheostat may thus be set for any value of equivalent 

 reactance and plugged into the network if desired. Direct- 

 current at 125 volts is used for operating the table, the negative 

 side being connected to ground and when it is desired to place a 

 short-circuit on any part of the system, that point is simply con- 

 nected to the ground in such a manner as to establish a short- 

 circuit through the rheostats representing the generators and the, 

 rheostats representing the interconnected network of lines. The 



