224 



A RMA TURE CONSTR UGTION 



same shape, and may 

 be made on one former. 

 In such a winding there 

 is more certainty of the 

 phases being balanced. 

 In all the previous 

 three-range windings 

 both ends of any single 

 coil are in the same 

 range, i.e. the ends of 

 the coil at both ends 

 of the armature are 

 in either the upper, 

 middle, or lower range, 

 as the case may. be. 

 In the present wind- 

 ing, considering a 

 single coil, at one end 

 of the armature it is 

 in the upper range 

 while at the other end 

 of the armature it is 

 in the lower range. 

 This will be clear, con- 

 sidering, for instance, 

 the black coils only 

 from Fig. 259, where 

 the diagram is shown 

 as a two-phase 

 winding. 



The two - phase 

 winding in Fig. 259 is 

 whole-coiled. Con- 

 nected as three-phase 

 the diagram is as 

 shown in Fig. 260, 

 where the winding is 

 now changed from 

 whole-coiled to half- 

 coiled, and has three- 

 quarters the number of 

 poles, the change being 



