WINDING OF ALTERNATING-CURRENT ARMATURES 303 



The ends of the coils are formed over a wooden block, which is 

 shaped and mounted on the job in the manner shown in Figs. 362 

 and 363. 



A slab of fibre between the winding block and the core end 

 flange distances the coil from the end flange. The block for this 

 case should just cover 6 slots which are left open for the front 

 range coils. 



The back range coils are wound first. 



FJG. 363. Arrangement of Winding Blocks for Hand Winding. 



The slot insulation is inserted, in the case of semi-closed 

 slots or tunnels, . by pushing the tubes in from the end of 

 the core. 



Slots Nos. 1 and 3 are now filled with 8 pins each, as there are 

 to be 8 conductors per slot. 



Let us suppose, for instance, that the winding is to be done 

 with S.W.G. 11 : the diameter of S.W.G. 11, bare, is 2'95 mm. ; and 

 double cotton covered, 3'20 mm. The pin should be of diameter 

 3-20, and the nearest standard wire to this is S.W.G. 10. 



