ALTERNATOR REGULATION AND OPERATION 



155 



70. Magnetomotive Force Method. In the synchronous 

 impedance met hod of determining regulation, a voltage was 

 nited for armature reaction or for a magnetomotive force. 

 In the magnetomotive 

 force method, a mag- 

 netomotive force is 

 substituted for a volt- 

 age, this voltage being 

 IX drop in the 

 armature of the alter- 

 nator. In other words, 



i mature reactance Fl - 156 - Vector diagram of magnetomotive 

 . , j . . force method at unity power-factor. 



is considered as being 



zero, but the armature reaction is increased a sufficient amount 



to compensate for this. 



Tin- method involves a short-circuit and an open-circuit test 

 and in this respect is similar to the synchronous impedance 



A 



In,. l.~>7. Open-circuit and sh< testa, magnetomotive force method. 



method. Figure l.'.ii >ho\\> the principle <>!' the method. This 



mi is c<i:>tructed for unity power-factor. F i minal 



voltage. To this is added the //,' drop, giving the voltage V\. 



