SYNCHRONOUS GENERATORS 



31 



with 216 slots. There are 12 inductors in series per slot. The 

 phase windings are connected in star. 



(a) What are the cross-magnetizing and demagnetizing 

 ampere turns per pole due to armature reaction when the 

 alternator delivers its full-load current at 0.85 power factor (in- 

 ductive load)? Assume that for this power factor the current 

 in any phase is 0.7 of its maximum value at the time the in- 

 ductors of that phase are under the center of the pole. 



(b) What are the cross-magnetizing and demagnetizing ampere 

 turns per pole due to armature reaction when the alternator 

 delivers its full-load current at 0.85 power factor (condensive 

 load)? Assume that for this power factor the current in any 

 phase is 0.2 of its maximum value at the time the inductors of 

 that phase are midway between the poles. 



DATA ON ALTERNATING-CURRENT GENERATORS 



40. Calculate the cross-magnetizing and demagnetising ampnv 

 turn- in alternator A for full-load current and such a power 

 factor that the current is lagging and has a value of 0.70 of its 

 maximum value in any phase when that phase is opposite the 

 center of the poles. 



41. Calculate the cross-magnetizing an<l demagnetizing ampm- 

 turn- in alternator B for full-load current and such a p<>\vrr factor 



