48 



ARMATURE CONSTRUCTION 



segment of a disc. This angular motion is adjustable by index 

 plates, a number of which are supplied with the press. These 

 are so designed that, with a minimum number of index plates, a 

 maximum variety of numbers of slots may be obtained. 



The mechanical movements must be designed with a minimum of 

 inertia and of back-play, and must be capable of very rapid work. 



FIG. 42. The Stoll Automatic Armature Disc-notching Machine. 



A type of circular shear built by Messrs Zeh & Halmemann is 

 illustrated in Fig. 44. This machine is especially suitable for 

 cutting the segmental core plates for armatures of very large 

 diameter. To meet conditions where, in the case of large arma- 

 tures with segmental core plates, it is desired to avoid going to the 

 expense of a compound die, Messrs Zeh & Hahnemann have 

 developed a set of machines, which have been described on p. 180 

 of the American Machinist for 24th February 1006, from which 

 the following has been abstracted : 



