170 TREATISE ON ALTERNATING CURRENTS. 



currents in the stator- windings are solely due to the leakage field, 

 or those magnetic lines which cut the stator coils alone. The 

 running-coil should, therefore, be wound as near to the inside edge 

 of the stator core as possible, and the opening in the slots in which 

 it is wound should be greater than the air-gap between stator and 

 rotor. Further, the winding should be such as to give a fairly 

 high induction density in the iron, otherwise the demagnetizing 

 action of the rotor currents will, at start, have too great an effect, 

 a feeble starting- torque resulting. 



The star ting- coil, on the contrary, should be wound in closed 

 slots, since in this case a large equivalent self-induction is neces- 

 sary to give the required difference of phase between the currents 

 in the two stator-windings. Since it is only in circuit for a short 

 time, this coil can have fewer turns than the running-coil, and 

 carry a heavier current. 



