THE CONTINUOUS CURRENT GENERATOR 147 



furnishing load altogether and will operate as a motor 

 from the other generator. 



The external characteristics of the two machines are 

 given in Fig. 94 at AB and AC. Suppose the load is 130 

 amperes and that machine No. 1 is supplying 50 amperes 

 and No. 2, 80 amperes, the bus-bar voltage being 115 volts. 

 Now something may happen to change the load on No. 1 



120 

 115 

 110 



I 



i 105 



I 



! 100 



10 20 30 40 50 60 70 80 90 100 110 

 Load on each generator 



FIG. 94. Curves to Show Load Division between Two Compound 

 Generators in Parallel. 



to 60 amperes and so its voltage rises to the point F on the 

 line AB. As the whole load is 130 amperes, machine 

 No. 2 will now carry only 70 amperes and so we should 

 expect machine No. 2 to operate at the point G of its external 

 characteristic. But the terminal voltage of No. 1 is now 

 higher than that of No. 2 and as they are connected to the 

 same bus-bars this is really an impossible condition. 

 Machine No. 1, however, being at higher terminal voltage 



