92 ELECTRICAL ENGINEERING PROBLEMS 



Ampere-turns 



2000 4000 6000 8000 10,000 12,000 14,000 16,000 18,000 



Volts (to neutral) 



940 1900 2600 2950 3160 3340 3460 3550 3620 

 3625 ampere-turns give full short-circuited current of 98.5 amperes. 

 Resistance per phase (to neutral) 0.33 ohm. 



Construct the above magnetization curve and the curve of short- 

 circuit current with ampere-turns. 



Construct also the pessimistic and optimistic zero-power-factor 

 curves between terminal volts and field ampere-turns (Karapetoff, 

 II, 143) and determine the two regulations for 5000-volts full-load 

 zero power factor. (30 r^in.) 



7. Determine also the pessimistic and optimistic values of 

 regulation for unity and 80% power factor. (20 ram.) 



