THE ALTERNATING CURRENT GENERATOR 247 



the pole. In some cases this effect has been the factor 

 that limited the output. 



Single-phase Armature Reaction with Inductive Load. 

 Suppose now that the single-phase generator is carrying 

 an inductive load. The current in the armature will have 

 the same m.m.f. locus as it had in Fig. 150, but this circular 

 locus will be rotated toward the right as shown in Fig. 

 151. This represents the conditions for a lagging load 

 of power factor =.7((j> = 45). It may be seen that the 

 components OA and OA', of a pair of vectors, no longer 

 neutralize one another; in fact with cos $ = .7 (Fig. 151), 



FIG. 151. Locus of Armature Reaction of a Single-phase Generator, 

 Lagging Current. 



both of these represent a demagnetizing action on the main 

 field. The sum of all the demagnetizing and magnetizing 

 components shows the net result to be a demagnetizing effect 

 for a lagging load. The cross-magnetizing effect is still 

 present but not to such an extent as it was for cosc{>=l, 

 because during part of the alternation the cross-magnetizing 

 effect pushes the main^ field into the leading pole tips. This 

 would be the effect of the cross-magnetizing component 

 of Of, for example. 



The result of these combined actions is that the armature 

 reaction of a single-phase generator, furnishing current to 

 an inductive load, not only makes the main field pulsate 



