TRANSFORMERS 



299 



E.m.f . E 2 in the secondary = e.m.f . EI = E 2 in the primary. 



E.m.f . E in the secondary = e.m.f. E in the primary. 



nz 



Current 1% in the secondary = current I' = 1% in the primary. 



Resistance r 2 in the secondary = resistance ( -- ) r 2 in the primary. 



vw 



Resistance x^. in the secondary = reactance f M x 2 in the primary. 





FIG. 274. Circuit diagram of a transformer. 



n '* 



16. 



-^i ) 2 R 



FIG. 275. Equivalent circuit diagram of a transformer. 



Fig. 275 corresponds to equation 288. If the exciting current 

 is neglected, as in equation 289, the circuit may be simplified as 

 in Fig. 276. 



From this 



R + JX) , 



or 



where 



r = TI + ( ) r 2 is the resistance of the transformer expressed as 



