INDUCTION MOTOR 



357 



inductive load. It must therefore be operated in parallel with 

 an alternator of sufficient capacity to supply both the wattless 

 current to excite the induction generator and also the watt- 

 less current required by the load. (Fig. 337.) Since the exciting 

 current is about 30 per cent of full-load current the induction 

 generator is not suitable when the load power factor is low. 



Synchronous Alternator Induction Generator 



FIG. 337. Induction generator. 



The alternator which provides the exciting current for the in- 

 duction generator and thus determines the frequency of the 

 system may be located in the receiving station and will then 

 supply the wattless exciting current back over the line. This 

 tends to improve the power factor of the line and the voltage 

 regulation since a lagging current supplied from the receiver end 

 to the generating end is equivalent to a leading current in the 

 opposite direction. 



In construction the induction generator is the same as an in- 

 duction motor and a squirrel-cage rotor may be used. 



