150 



ARMATURE CONSTRUCTION 



windings are, so far as location in the slot is concerned, susceptible 

 to a number of arrangements ; that shown in Fig. 330 is, however, 

 the most customary. The upper twelve conductors are, before 

 being placed in the slot, made up into a twelve-turn coil with six 

 ends, in the manner shown in Fig. 331, p. 279, or in Figs. 308 and 

 309, p. 264. 



FIG. 176. Multiple-circuit Winding 

 three-turn coil. 



FIG. 177. Two-circuit Winding 

 three-turn coil. 



Now we come to the question of the influence of the number of 

 slots on the choice of yf and yb for two-circuit windings. Suppose 

 that we wish to design a 4-pole winding for a 57-slot armature, 

 and to employ the coil illustrated in Figs. 330 and 331. There 

 are to be three segments per slot, and four turns per segment; 



\ 



FIG. 178. FIG. 179. 



Single turns representing three-turn coils. 



thus there are six terminals per coil. The twelve upper con- 

 ductors of one slot constitute one side of a compact " coil," of which 

 the other side shall comprise the twelve lower conductors of some 

 other slot. While there are actually 



57x24 = 1368 

 face conductors, we shall consider each group of four conductors 



". . ELEC 





