THEORY OF SYNCHRONOUS MOTOR 



on the stable descending branch is reached. Along any descending 

 branch, the condition of stability is satisfied, a momentary retardation 



1000 



-1200 



^RCClON '.. OF *.. 



-800 



-600 



-200 



ANCrLE OF ADVANCE OF MOTOR E.M.F. 



Fio. 98. Variation of Current with Angle of Advance of Motor e.m.f. 



resulting in an increase of driving power, and a momentary accelera- 

 tion in a decrease. The conditions represented by the dotted branches 



-600 



-500 



-'too 



-300 



'-'~^N> 



\ 



--'-^'j \ 



REfilON /OF/ 

 INSTABIl/'T/f , 



-200 



ANCLE OF ADVANCE OF MOTOR. E.M.F. 



Fio. 99. Relation connecting Driving Power with Angle of Advance of Motor e.m.f. 



of the power curves could therefore exist only momentarily as, e.g., 



