CHAPTER XII 



THE WINDING OF ALTERNATING-CURRENT ARMATURES 



IN treating the subject of the winding of alternating-current 

 armatures it will be convenient if we take them under the types 

 as classified in Chap. IX., dealing with alternating-current armature 

 winding diagrams. 



In that chapter we gave a number of photographs of the various 

 types of winding side by side with their winding diagrams, and 

 from these a good deal may be learnt respecting the construction 

 and the finished appearance of the windings. In the present 

 chapter we shall consider the methods of carrying out the various 

 windings. 



In Chap. IX. we classified the alternating-current windings 

 under six headings : 



A. Spiral coil. 



B. Lap coil. 



C. Wave.' 



D. Retrogressive wave. 



E. Skew coil. 



F. Short coil. 



The difference between these types is seen on reference back to 

 Fig. 236. 



A. Spiral-Coil Windings. Spiral coils may be either hand- 

 wound or form-wound, generally according as the slots are totally 

 or semi-closed, or wide open. 



The question is also affected by whether the coil is a single, 

 double, or triple coil (see Fig. 237), as a triple coil, if form-wound, 

 would require three different sized forms, and ;i quadruple coil four 

 forms, and so on. For this reason if the coil is more than a double 

 coil, it will usually be hand wound. 



Hand Winding. We shall consider first wire windings by hand, 

 and then strip windings. 



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