240 



ELECTRICAL MACHINERY 



Three-phase Winding. This same armature might be 

 wound three-phase by dividing the twelve coils into three 

 groups of four coils each and properly connecting them. 



To slip ring 



T 



To slip ring 



FIG. 144. Developed Single-phase Winding, Using Concentric Coils. 



The connections for a Y-winding are shown in Fig. 146 

 ' and in Fig. 147 are shown the connections for a A-connected 

 armature. It will be noticed that the connections of 



Slip ring #1 Slip ring #2 Slip ring* 3 Slip ring * 



r Fia. 145. Developed Two-phase Winding. 



the coils in these two figures are electrically the same as that 

 given for the elementary one-coil-per-phase machine shown 

 in Fig. 141. 



