TRANSMISSION OF POWER BY ALTERNATING CURRENT 4ffl 



174. Motor-generator and Synchronous-converter Substa- 

 tions. It is often necessary to obtain direct current, either 

 for power supply to a thickly populated district or for electric 

 railways. As has been pointed out (page 342, Par. 137), either 

 the synchronous-motor-generator set. the induct ion-motor- 

 grnerator set, or the synchronous converter may be employed 



8 Ph. Incoming Lines 26,400 V. 

 L.A. 



10 V. 



S-Ph. 2300 -Volt BOB 



frPh. Outgoing Lines 2300 V. 

 J72. Typi tnuisformer sub-station. 



for d 'In- ;dtcni;itinL r -ciirrent supply into direct current. 



The ;idv;mt;iL r e of the synchronoii^-n Merator set is that 



its power-factor may be mm rolled; it- disadvantage is it> 

 <|ency to f.-ill (ut of step when line di-t iirlmnce- occui\ The 

 advantage of the induct ion-mot or-uenerator set i- that the in- 

 duction motor tends to com in oven when severe line 



