WINDING OF ALTKRNATING-OURRKNT ARMATURES 301 



The common method of wire winding with semi-closed or 

 tunnel slots may be designated " pin-winding." In this method 

 the slots are filled with a number of wire pins of diameter equal 

 to the diameter of the covered wire with which the armature is 

 being wound, and equal in number to the number of conductors 

 required ultimately in the slot. 



FIG. 361. Wound Stator for Induction Motor. Eight-pole, Three-phase, Half-coiled, 

 Triple-coil, Three-slot, Spiral -winding (Scott & Mountain). 



The pins project a few inches out of the slot at each end of the 

 armature, and the process of winding consists in pushing each pin 

 out of the slot with the end of the wire and so proceeding until all 

 the pins have been extracted, and the slot is filled with the wire 

 conductors. 



It may be well to take a concrete example, and for this let us 

 consider an 8-pole 3-phase stator having 72 slots and 8 conductors 

 per slot, the coils to be laid up in two ranges. We have seen on 

 p. 191 that a 2-range o-phase winding must be half coiled ; hence 



