330 ARMATURE CONSTRUCTION 



by one layer of bond paper with two layers of elastic tape. 

 The insulation is of such width as to leave inch on each side 

 of the bands. 



The banding wire is 0'045 inch diameter medium hard steel, 

 tinned. The tensile strength of this wire is about 204 Ibs., and 

 the tension put on the wire during banding is about 100 Ibs. 



After the recess in the core is filled with the banding wire, it 

 is soldered up. 



The wires are held by small clips of tinned copper, which are 

 applied in the manner of Figs. 409 and 410, being placed under 

 the wire during -band ing, and closed over as in Fig. 410 when 

 all the wire is on. There would be four to six clips for each 

 band on armatures up to half a meter diameter, and on larger 

 armatures one clip for about every 25 cms. of periphery. The 



FIG. 409. FIG. 410. 



Clips for Binding Bands. 



clips are then sweated up, and solder run in all round the wires 

 on each band. 



The soldering should be very carefully done, and care should 

 be taken that the wire is clean from any grease or oil before 

 soldering. 



In larger factories it is customary to provide special lathes 

 exclusively for banding. Fig. 411 shows one such machine. 

 This runs at about 30 r.p.m. It has a self-contained tension 

 and feeding attachment, the latter of which is seen in front 

 of the lathe bed. 



Fig. 412 illustrates another machine for this purpose. It will 

 take armatures up to 31 inches diameter and 98 inches length 

 of shaft. The machine is electrically driven with a IJ-h.p. motion 

 in the base of the headstock. 



The headstock spindle has four speeds, 12, 24, 100, and 200 

 r.p.m., operated by a single lever. 



The wire feed carriage is traversed bodily by rack and pinion 

 from the one binding place to the other, while the top wire guide, 



