THE ARMATURE FRAME 



63 



core rests against this flange at one end, and there is a 

 detachable flange at the other end of the armature to clamp 

 the core in place. 



Figs. 67 and 68 illustrate front and back views of a 1500 

 k.w. alternator armature frame. In Fig. 67 will be noted the 



FIG. 59. Armature Spider of 1000 k.w., 16-pole, 90 r.p.m. Generator. 



fixed end flange similar to that in Fig. 66. This frame is split 

 into two equal parts with a horizontal division, as is necessary 

 in very large frames. Fig. 68 shows the skeleton structure of 

 the frame ; it consists of an inner and outer shell, the inner 

 pierced by a large number of apertures webbed together by 

 axial and circumferential ribs. A section through a frame 

 of the same type as Figs. 67 and 68 is shown in Fig. 69. 

 In this case both the inner and outer shells are perforated with 



