ALTERNATING-CURRENT TRANSFORMER. 



is easy to correct the diagram with regard to the ohmic resistance of 

 the primary, if this should be desired. 



155. Let O Q, Fig. 47, be the e. m. f. necessary to overcome the 

 ohmic resistance of the secondary circuit, including the resistance of 

 the coils of the transformer, and O N the e. m. f. required to over- 

 come the external inductance in the secondary circuit, then O P is 

 equal to the e. m. f. required to drive the current through the whole 

 secondary of the transformer. The field necessary to do this is O G, 

 in quadrature with E t . C G is the leakage field of the secondary, C A 

 is the secondary m. m. f. X t , O A the primary m. m. f. X\. C D is the 

 primary leakage field. O C is the common magnetic field, and the 

 scale of Xi and X 2 is so chosen as to give a resultant equal to O C = 

 F. O K is constant as O D is constant, O K being equal to Vi . O D.* 



It follows at once from the diagram, 



AK : X, : : X, : -~ 



Vl 



AK = v, . X,. 



As angle O G K remains constant and equal to 180 P O N, G 

 moves in the arc O G K. If the diagram is constructed for one point, 

 the locus of G is determined. 



156. To determine the locus of A we have to consider the ratio be- 



tween G K and A K, which we have called 



KC = X, (i vj 

 For A K we have Vi . Xi, hence 



G~K - -- i i 



a = -- = v t = - -- I 



A ~K *i ^ 



This diagram is identical with that given by Herr Emde in the Eltktrottch- 

 ische Zeitschrift, Oct. n, 1900. I refer the reader to Herr Erode'* important 



"al* 



ITC. 



85 



contributions on this subject, as well as to his valuable criticism of my paper of 

 1896 on the general transformer. See also Herrn Heubach's, Kuhlmann's, and 

 Sumec's letters on the same subject there. 



