270 



ARMATURE CONSTRUCTION 



the armature windings. This method of binding up the equaliser 

 rings into a solid group yields a compact job, and the arrange- 

 ment will be more clear from the sectional sketch in Fig. 319, 

 which was prepared in 1901 according to the directions of H. M. 

 Hobart, to whom the arrangement is due. 



Fig. 320 shows a large armature, designed by one of the authors 

 in 1901, with the equalisers done up in this way. The method 



FIG. 320. Large Armature, showing Equaliser Ring Construction 

 (Union Electric Co. of Berlin). 



employed by the General Electric Company (U.S.A.) is illustrated 

 in Fig. 321. In this method the rings are spaced from each other 

 and from the armature body by grooved wooden blocks placed at 

 intervals around the armature. 



It has occurred to the writers that the most useful way to deal 

 further with the matter will be to describe the forms and accessory 

 tools which should be provided for dealing in an up-to-date manner 

 with the requirements of certain concrete cases. 



Let us begin with the case of a strip-wound, 6-pole, 250 

 k.w., 320 r.p.m., 550-volt railway generator, whose slot cross- 



