POLYPHASE CIRCUITS 



119 



With the synchronous motor running at no load and with under 

 'xcitation the line current has its full-load value of 42 amperes, 

 the line voltage at the motor is 13,200 volts and the power 

 supplied to the motor is 28.6 kw. At this time the field excita- 

 tioii of the generator is 161 amperes. 



When the motor load requires 1000 kw. what must be the 

 excitation of the generator in order that it shall operate at unit 

 pmvrr factor 2 and the line voltage at the load shall be 13,200 

 volts/ What is the power factor of the load? 



65. A 3500-kw.. 10,000-volt, 2-phase alternating-current 

 a tor delivers power through Scott transformers to a three- 

 phase transmission line. With the far end of this line short- 

 circuited the output of the generator is 490 kw. and the armature 

 current and terminal voltage are 220 amperes and 1630 volts. 

 On open circuit the high-tension line voltage is 33,000 volts when 

 the terminal voltage of the generator is 10,000 volts. The arma- 

 ture has an effective resistance of 0.64 ohm per phase The open- 

 :iml > hurt -circuit characteristics are: 



1 1 t here is a load requiring '.Jiio kw. at 0.91 power factor at the 

 end of the line, what inuM he the excitation of generator in order 

 that the lino voltage at the load shall he 30,000 volts? (Use the 

 magnetomotive-force met hud when dealing with the generator.) 



66. A innn-U.. 13,800-volt. ii-phase alternating-current 

 .it or deli \ver over I transmission line which has a 



he nrmatun -,\ imlingB are connected in N 



ist also be properly adjusted for this to 





