204 ARMATURE CONSTRUCTION 



this term should not be confused with the terms single coil, double 

 coil, etc. 



It will be seen that there are three factors employed in deter- 

 mining a winding, viz: (1) Whether it is whole-coiled or half- 

 coiled ; (2) the multiplicity of the coil whether single or multi- 

 coil ; (3) the number of slots per pole per phase whether uni- 

 slot or poly-slot. 



It will also be appreciated from the relations set forth in Table 

 XIV. that any two of the factors determine the other remaining one. 

 Consequently it would be quite sufficient in describing a winding 

 to state only two, which is the case in Figs. 237, 238, and 239. 

 In these figures the two factors set forth are Nos. 1 and 2, but 

 these figures could have been just as well prepared from the basis 

 of factors 1 and 3, i.e. whether whole-coiled or half-coiled, and the 

 number of slots per pole per phase. 



As the system in this chapter has been evolved from the two 

 factors 1 and 2 we shall adhere to this designation in studying 

 the windings which now follow, but we shall also add to the title 

 of each winding the factor 3, the number of slots per pole per 

 phase, uni-slot, two-slot, etc. 



It may be noted that the latter figure is the one which the 

 designer employs for the winding in any particular case, and it is 

 also more convenient in the case of wave windings (see p. 229). 



APPLICATION OF NOMENCLATURE SCHEME. 



Two-range Windings. 



We now give a number of photographs of various different 

 windings which we shall study by means of their diagrams, and 

 the application of the above system of nomenclature to them. 



Fig. 240 shows a photograph of a stationary armature having 

 seventy-two slots wound with twelve coils. This winding is a 

 two-range winding, there being thus six coils in each range. 

 Fig. 240 shows clearly one range laid back against the frame, and 

 the other standing in front of it. Each coil is distributed over 

 three slots at each side. If there were only one conductor in each 

 slot, then the winding diagram of Fig. 241 would be a true repre- 

 sentation of the actual winding. 



The winding would actually consist of several conductors per 

 slot, as will be seen from the thin connectors between the coils ; 

 but if each radial line in Fig. 241 is regarded as a group of 

 conductors, the same in number as there are conductors per slot, 

 the diagram of Fig. 241 will represent the winding. 



