THE TRA\WOItMER 



183 



- be noted that the vector diagram of Fijj;. 1 76 (a) is similar to that 

 of the alternator. The voltage l'i is ^iven by 



T! = V(F 2 cos 9 + WZo) 2 + (F 2 sin 6 + 7 2 X ) 2 (49) 



/? is the equivalent resistance of the transformer and X is the 

 equivalent reactance. Obviously I\ could be substituted for 7 2 

 in the foregoing equation. 



Example. A 40-kv-a., 220-volt, one-to-one transformer has a primary 

 resistance and a secondary resistance each equal to 0.009 ohm. The leakage 

 reactance of the primary is 0.037 ohm and that of the secondary is 0.043 



Transformer 



Fig. 176 (&) Relation of Impedance 

 Drops when the Ratio of Transformation^ 



Load " otber tbnn Ouily 



Fl| r.6(c) Equivalent Ciuult 

 of tLc Itausfoimar 



Fig.l7<i(a)simpll.'ied Vector 

 Diagram of Transformer 



FlG. 176. 



I. Determine the regulation of the transformer at full load, 0.8 power- 

 factor, landing ''urrent. 



R = 0.009 + 0.009 = 0.0 is ohm 



A IN M7 4. Q.Q43 0.080 ohm _ 

 V l = V(220 X 0.80 + 182 X 0.018)' + (220 X 0.60 + 182 X 0.080)' 



- 232 volts. 



/Nation 



_ 220 



= 5- 4 6 P'r <-<-nt. Ana. 



n-milatinn i< not strictly true because V t is assumed to 

 lo fixi-l ;ui<l I', to vary as the load dianiros. In a tr:in>fonn<T, 

 tin- primary voltaic- \l ordinarily Ji.rl and the secondary voltage 

 d. As the n-uulat ion is small, littk* or no 



