THE I\I)r<-TH>\ MOTOR 



231 



100. Rotating Fields in Drum-wound Machines. The coal- 

 men iul polyphase induction motor consists of a fixed member 

 called the stator, carrying a polyphase drum winding (like that 

 of an alternator), and a rotating member called the armature or 

 rotor. As the stator usually receives the power from the line it is 

 railed the primary, and as induced currents flow in the rotor, it is 

 called the secondary, just as in the transformer. The motor will 

 operate, however, if power is supplied to the rotor and the stator 

 acts as secondary. Stator windings are the same as alternator 

 windings for the same number of phases and poles. In fact, the 



rh.te A 



IK. _'_':*. Siimlc-laycr. -l-polo. 'J-phnso induction motor winding. laj>-connected. 



ordinary alternator winding is entirely satisfactory for an induc- 

 tion-motor winding. 



are 223 shows a single-layer, drum winding for the two- 

 phase, four-pole, induction motor stator shown in Fig. M. In 



thi> machine then- arc six slots per pole or three slots per pole 

 per phase. Only the one phase. .1, is shown connected. 



-ire 224 shows a section of this two-phase induction motor, 

 taken perpendicul:,!- to Itfl >haft. It is wound with the two- 

 phase, four-pole winding, shown in Hie time variation 

 of the two-phase currents. / , and /. is also shown. 



At < he current / tV6 maxi- 



mum. By applying tin determining th< 



