

DETAILED STUDY OF OPERATION WITH NORMAL LOAD 85 



It is seen that the curve of the saving which results from the use of 

 synchronous motors working jointly with induction-motors, rises rapidly, 

 id that it becomes positive for values of cos (J> which are all the 

 reater the better the efficiency of the synchronous motors. 



Regulation of Distribution-Voltage. The over-excitation of syn- 

 chronous motors can, incidentally, enable the voltage to be raised 



Generator Em.f 

 FlG. 41. 



at the terminals of motors and transformers connected with the line, 

 and even at the terminals of the generator. The possibility of this 

 is readily seen in the case where the line has a negligible resistance and 

 reactance, and where there is only one generator and one motor 

 which are both alike. The difference of potential at the terminals 

 (Fig. 41), is OB (B being at the middle of AiA2), and by increasing 



A. Internet/ e m.f of generator 



FIG. 42. 



OA<2. this difference of potential can always be made as large as 

 desired. 



In the general case, by drawing, successively, with their phases, 

 three vectors equal to the products of the current A\C by the impedances 

 of the generator, of the line, and of the motor, we obtain a broken line 

 A\BDA<z (Fig. 42). The voltages at the terminals of the generator 

 and of the motor are OB and OD; and A 2 can always be sufficiently 

 increased so as to make OD and OB greater than OA\. 



