CHAPTER VIII 



CONTINUOUS-CURRENT ARMATURE WINDING SYSTEMS 



FOR all except comparatively small designs, a type of armature 

 winding known as a " Multiple-Circuit Winding " is almost 

 exclusively employed for continuous-current machines. This 

 winding owes its name to the circumstance that there are as many 

 conducting paths (circuits) for the current to traverse in passing 

 through the armature from the negative to the positive brushes, 

 as there are poles in the machine. Multiple-circuit windings may 

 either be ''simplex " or they may be " multiplex " (i.e. duplex, triplex, 

 etc.). Multiple -circuit multiplex windings are, however so little 

 employed that it is not convenient to always state explicitly that 

 a certain armature has a multiple-circuit simplex winding. It is, on 

 the contrary, customary and practicable to simply state that it has 

 a multiple-circuit winding, arid to realise that, if it had a duplex or 

 triplex winding, it would be explicitly stated that it had a multiple- 

 circuit duplex winding or a multiple-circuit triplex winding, as the 

 case might be. So let us, for a considerable part of this chapter, 

 completely dismiss from our minds the knowledge of the existence 

 of any type of windings other than multiple-circuit simplex wind- 

 ings, and let us refer to these as " multiple-circuit " windings.* 



Let us, furthermore, begin by limiting our thoughts to 

 windings with but one turn between adjacent commutator seg- 

 ments. Such an elementary turn, with its corresponding com- 

 mutator segments, is illustrated diagram ma tically in Fig. 151. 

 Suppose that this is a turn of a 4-pole winding with 96 segments ; 

 then there will be 96 turns, and hence 2x96 = 192 face con- 

 ductors. If, as in Fig. 152, we denote the left-hand conductor by 

 1, then the number of the corresponding right-hand conductor of 

 this single turn will be found by adding 



47or49 to 1. 



* A chart showing the derivation of the types of continuous-current 

 windings is given in Plate XIV. 



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