INDUCTION MOTOR 



329 



The m.m.f. of phase 1 is nJ Q cos 6 in direction OA. 

 The m.m.f. of phase 2 is ni! cos (6 120) in direction OB. 

 The m.m.f. of phase 3 is n-J Q cos (6 240) in direction OC. 

 The resultant m.m.f. in the horizontal direction is 



x = nJ cos + nJo cos (0 - 120) cos 120 + nJ Q cos (0 - 240) cos 240 

 = ni/o j cos ;r (cos cos 120 + sin sin 120) 



- H (cos cos 240 + sin sin 240) j 



3 3 



= nJ Q - cos = - 



- Z 



cos 0. 



FIG. 313. 



The resultant m.m.f. in the vertical direction is 

 m Y = Ul I | cos (0 - 120) sin 120 + cos (0 - 240) sin 240 } 



-7T- (cos cos 120 + sin sin 120) =- (cos cos 240 



+ sin sin 240) > 



-s- 3 sin = jr 







sin 0. 



