THE INDUCTION MOTOR. 



sistance of which is six times as large as that of the armature with 

 external starting resistance. 



123. Fig. 35 shows the power factor and the efficiency for the two 

 cases. The power factor is, of course, the same in either case. In the 

 calculation of the efficiency the load-losses have not been taken into 

 account. 



124. Finally, we have in Fig. 36 a graphic representation of the out- 

 put and the torque in watts as a function of the slip in p. p. s., or rath- 



mo 150 



K.W. 



FIG. 35. 



er, of the number of revolutions of the armature expressed in p. p. s. 

 The broken line curves refer as usual to the squirrel cage armature. 

 Little need be said about these curves. It is plain that for the arma- 

 ture with a small resistance the starting torque is still exceedingly 

 small at ~ 2 = 40. Such a motor will never start well without extra 

 resistance in the armature, whatever starting arrangement be made. 



68 



