370 



ELECTRICAL EQUIPMENT 



of resistances marked R-l, R-2, and R-3, respectively. These 

 resistances in series are connected in parallel with the storage 

 battery and the main exciter. The booster exciter field connec- 

 tion is made between resistance 72-1 and R-2, while resistance R-3 

 is short-circuited by means of the regulator relay contacts. These 

 resistances are so proportioned that R-l is considerably greater 

 than R-2, and that R-2 plus R-3 is greater than R-l. It will 

 be readily seen that when R-3 is short-circuited by the regulator 

 contacts the direction of excitation upon the booster exciter field 



Feeders 



FRONT VIEW Non Inductive 



Resistance 



FIG. 222. Type T.A. Voltage Regulator in Connection with KR System of 



Regulation. 



will be in one direction; and when this resistance R-3 is inserted 

 in circuit by means of the relay contacts being open, the direc- 

 tion of excitation through the exciter field will be in the opposite 

 direction. 



The design of the above resistance is also such that there will be 

 full excitation upon the booster exciter in each instance, making it 

 possible to obtain the full boosting and bucking condition upon the 

 main D.C. booster. Assuming that the voltage of the main 

 exciters is 250 and that the D.C. booster is capable of giving 50 

 volts in each direction it will at once be noted that the voltage 



