Till-: ALTERNATOR 



109 



"'(J pitch. A coil instead of having a pitch of 12 slots, 

 now has a pitch of 10 slots, so its spread is no longer equal to 

 a full pole-pitch. This is a fraction a l-pitch winding. 



The advantages of this type of winding are that it improves the 

 wave form, there is an appreciable saving of copper in the coil 



Fio. 112. Three-phase, ^-pitch, 2-layer lap winding, four slots per pole per 



phase. 



, and tho inductance of the winding is reduced, because of 

 th<- lesser mutual inductance between those conductors which lie 

 in slot< containing conductors of the other two phases. (See 

 Fitf. 112.) The coil-end inductance is also reduced becai; 

 the lesser length of free conductor. Such windings generate 



(a) Full piti-h. r-:i-ti.n:il pit.-h. 



IK.. 1 vnlt.'iKrs iii fiill-pit-li and ii. i-pit. -h 



windings. 



slightly lcs> emf. than full-pitch windings under the s:une condi- 

 tion-, BU106 the two mil >ides do Hot lie under the sam 

 the p<le at any niven instant and 1 1 heir emf-. are >liL r hl ly 



fas than isn apart. 'l'hi< is ilhwtnrted in 1 i la the 



cmf. induced in the conductors comprising , mil and 



