TH1 



THE ARMATURE REACTIONS OF ALTERNATORS 239 



The dephasing ([> of the current is regulated entirely by the numerical 

 value of the transverse reaction, which, on the contrary, has little effect 

 upon the E.M.F. 



This proposition has been demonstrated in the case of unsatu- 

 rated armatures, as I have just stated, but it is general and remains 

 in effect even in the case where the circuit of the transverse reaction 

 approaches saturation. The demonstration of this will be given below. 



Diagram of E.M.F. 's and Currents of an Alternator with Unsat- 

 urated Armature and with Saturated Field Magnet. The diagram 

 in Fig. i 1 reproduces Fig. 5 of my first paper, supplemented by the 



definitions of Fig. 2. r' represents the apparent resistance, that is 

 to say, the ohmic resistance augmented by the effects due to Foucault 

 currents; is the difference of phase in the external circuit, and 

 is the difference of phase with respect to the internal E.M.F. It is 

 proposed to calculate the excitation necessary to develop an E.M.F. 

 U at the terminals under a current-delivery I dephased by <j>. We 

 have OP=r'I and PA = U, with the angle APa=(j>. 



Let OT be the direction, as yet unknown, of the internal E.M.F. 

 e; the perpendicular AB let fall from A upon OT 1 is the sum of the 

 transverse reaction: 



AG=a>lI cos (}>, 



1 The subscript w indicates the active or energy component and the sub- 

 script d the reactive or quadrature reactive component. 



