112 



ARMATURE CONSTRUCTION 



Another method, suitable for small standard commutators, is 

 illustrated in Fig. 129, which is self explanatory. 





FIG. 127. 75 li.p. Commutator before pressing into the Building Ring. 

 Vickers, Sons & Maxim. 



For applying heat, perforated gas-pipes are bent in a circle to 

 correspond to the inside and outside surfaces of the ring of 

 segments, the perforations being on the side of the pipes facing 



FIG. 128. 750 k w. Commutator in Building Ring ready for turning. 

 Vickers, Sons & Maxim. 



the copper, as indicated in Fig. 126. A suitable temperature is 

 attained by adjusting the relative supplies of gas and air. The 

 copper should be heated to a temperature of some 150 Cent. The 

 clamping blocks should be tightened, little by little, by means of 

 the radial bolts, as the heat drives the cement out from the mica. 



