ADDITIONS TO THE THEORY. SECOND APPLICATION 105 



Fig. 460 shows how the values necessary for constructing the 

 ''-curves are obtained; and Fig. 490, represents the case where the 

 ichronous motor is operating with constant excitation and at con- 

 stant potential. 



FIG. 493. 



These diagrams give a degree of precision which is generally 

 sufficient for practical purposes, being intermediate between that 

 obtainable with the simplified methods used in Chapter II and the 

 more rigorous method used in Chapter III. Moreover, the diagrams 

 440, 460, 49a express armature-reactions in terms of magnetomotive 

 force more precisely than if the total zl resultant were to be expressed 

 by a magnetomotive force. 



