Tin-: ALTERNATOR 



107 



add two more windings, equally spaced, between those of Fig. 103 

 in order to obtain a three-phase winding having one slot per pole 

 per phase. The three phases of Fig. 109 may be connected 

 either in Y or in delta. 



A ' B C A i B C I A I B C ' A 



\ 



1"!). Three-phase, 2-layor winding, one slot per pole per phase. 



Figure 110 shows a three-phase chain winding, in which their 

 are Ol slot- per polo, making two slots per pole per phase. This 

 is a two-range winding, for the coil ends in order to pass one 

 another must lie in two different planes perpendicular to the 

 machine shaft. If the number of coil groups per phase is odd, 

 which occurs if the number of p<>le< is not a multiple of four, coils 

 having one long side and one >h.rt <ide must be used to com- 

 plete the winding. This occurs in the six-pole winding OJ 

 I in. in which two coils <l and (V must be of trape/oidal >hape in 

 order to pass the roil ends of phase A and so complete the winding. 

 A plan view of <uch coiN i- shown at (a . I ' 110, Six dif- 

 of coils are required in this winding, making it : 



