GENERAL THEORY OF THE INDUCTION MOTOR. 289 



dependent of motor load) to a given induction motor running at 

 slip s. Figure 250 is exactly like Fig. 215, and Fig. 251 is 



Supply main 



Exact equivalent of an induction motor.* 

 Fig. 250. 



exactly like Fig. 2 1 6 (see Art. 1 20). The circle diagram of the 

 induction motor, Fig. 242, is based on Fig. 251. 



The algebraic formulation of the action of the induction motor 



Sapply wain 



{supply mam 



Approximate equivalent of an induction motor. 



Fig. 251. 



may be easily accomplished on the basis of either Fig. 250 or 

 Fig. 251. On the basis of Fig. 250 the algebraic formulation of 

 the induction motor is as follows : The reactance X (equals &P) 



* A slightly more exact equivalent would be that in which part of the leakage re- 

 actance X is on each side of the point a, inasmuch as the forcing of the leakage 

 flux between stator and rotor windings by the load currents I' and I" as shown 

 in Fig. 241 makes it unnecessary for the magnetizing current to force this flux through 

 the reluctance of the rotor iron. The placing of X partly on each side of the point 

 a amounts to assigning a part of the magnetic leakage reactance to the secondary ; 

 and in fact the only basis on which leakage reactance may be separated into primary 

 leakage reactance and secondary leakage reactance is this basis of reluctance of rotor 

 iron. See Art. 117. 

 20 



