144 



ELECTRICAL MACHINERY 



machines; it is supposed that at no load the two machines 

 generate the same e.m.f. This is brought about by varia- 

 tion of one or the other of the field rheostats. Machine 

 No. 2 is supposed to have an external characteristic that 

 drops with load increase more than that of No. 1. When 



120 



115 

 110 

 105 

 ,100 



! - 

 ; 95 





>1 



10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 

 Load on each generator 



FIG. 92. Curves to Show Division of Load between Two Shunt 

 Generators in Parallel. 



the load is 140 amperes evidently No. 1 must be supplying 

 90 amperes and No. 2 supplying 50 amperes and the line 

 e.m.f. (i.e., the terminal voltage of the two machines) is 

 105 volts. 



If the load current is increased until the bus-bar voltage 

 falls to 100 volts machine No. 1 must be carrying 130 



