9-B] 



INDUCTION GENERATOR. 



299 



depends upon the speed of the generator, Fig. 5, and the field 

 excitation of the synchronous machine, Fig. 4. 



One synchronous machine, either in the station or in a substa- 

 tion, is sufficient for the operation of several induction generators. 

 In the case of a long transmission line, it has been proposed to 

 locate the synchronous machine at the receiving end so that the 

 leading current supplied to it will improve the regulation of the 

 line. 



PART II. TESTS. 



10. (a) Operation in Parallel with a Synchronous Generator 

 or Supply Line. The induction generator is driven by mechanical 

 power. As a driving motor, a shunt motor will be found con- 



Induction 

 Generator 



Synchronous Generator, 

 Motor or Converter 



To Load 



FIG. 2. Connections for operating an induction generator. The switch S 2 

 may connect to a supply line. 



venient since its speed can be easily varied. The connections* 

 are shown in Fig. 2. 



ii. Loading Back Test. No load is used, the switch S 3 being 



* ( ioa). The connections shown are for single phase; three ammeters 

 and three wattmeters may be used, or one ammeter and one wattmeter can 

 be switched from circuit to circuit. When polyphase apparatus is used, as 

 a laboratory test it may be operated single phase for simplicity. When 

 operated polyphase, the usual disposition of instruments should be made; 

 care should be take that the polyphase connections are so made that the 

 induction machine would run as a motor in the same direction it is driven 

 as a generator. 



