ASSEMBLING THE ARMATURE CORE 



91 



The choice of method is, of course, dependent upon the factory 

 equipment ; but it may be said that in the case of small armatures 

 hydraulic pressure is generally employed. 



Where the external stator is the armature, as in Figs. 91, 

 92, and 93, the process is so closely similar to that above 

 described as to make it sufficiently understood from the illustra- 

 tions without further comment. 



In Figs. 94 to 102 a number of completely assembled 

 armature cores is shown. 



FIG. 99. Complete Stator of Induction Motor by Allmaima Svenska 

 Elektriska Aktiebolaget. 



In work of this nature, the pressure desirable in assembling 

 (whether obtained hydraulically or otherwise) is some 21 kgs. per 

 sq. cm. (300 Ibs. per sq. inch) gross surface of the laminations. If 

 the pressures fall materially short of this amount, a thoroughly 

 solid result cannot be ensured. 



In a particular instance, a pressure of 10 tons is used in 

 pressing up an armature core with discs of 300 mm. diameter. 



In small armatures it is not customary to hold the core 

 together with bolts passing through from one flange to another. 

 One method is that shown in Fig. 332, Chap. XL, in which the 



