ARMATURE CORE VENTILATING PIECES 



79 



side of each finger. These fingers may be curved or shaped in any 

 convenient way so that they will stand up firmly on the core plate 

 and offer least resistance to the ventilating air. 



In Fig. 79 the fingers are fixed to one core plate by means of 

 projections fitting into small slits punched in the plate. The 

 fingers are fitted into these slits one at a time, and riveted over by 



FIG. 83. Ventilating Spacing-piece. Vickers, Sons & Maxim. 



hand at the back of the plate, rendering them quite firm. This 

 is a very efficient construction, but the process of riveting the 

 fingers into the laminations by hand is rather laborious. 



Fig. 80 shows a satisfactory construction which is employed 

 in the B.T.H. 1500 k.w. 1000 r.p.m. turbo-alternators, supplied to 

 the Yorkshire Electrical Power Company. 



Figs. 81 and 82 show further methods of the British Thomson 

 Houston Co. and British Westinghouse Co., in which a single plate 



