188 



ARMATURE CONSTRUCTION 



into sections just referred to, when we come to study the photo- 

 graphs of various types of winding with their diagrams, later on in 

 this chapter. 



In Fig. 223 the coils are no longer collected in groups of three, 

 as in Fig. 229, and owing to this feature the armature cannot be 

 divided into sections without dismembering several of the coils. 



This winding is, however, capable of being laid up in two 

 ranges in the manner shown in Figs. 230c and 230d. 



-^j-\r-u^^ 



FIG. 229. Three-phase Half-coiled Winding (one coil per phase 

 per pair of poles). 



Turning back for a moment to two-phase windings, it will be 

 seen that the two-phase winding of Fig. 222 is similar to the three- 

 phase winding of Fig. 229 in that the armature can be divided into 

 sections without disturbing the coils. 



As, however, there are only two coils in each group, there 

 being only two phases, the ends can be laid up in two ranges. 

 This is also the case with Fig. 227, but neither this winding nor 

 Fig. 228 allows of the armature being divided into sections. 



The above windings are the fundamental polyphase coil 

 windings, and of them Fig. 227 is the most common for two-phase, 



