COMMUTA TOR CONSTR UCTION 



115 



clamping end plates. Fig. 131 shows a small commutator after 

 machining the interior and ends, assembled in a single ring as in 

 Fig. 128. 



The end clamping rings with their insulations are then put 

 in place, adjusted, and tightened up, preferably by the application 

 of hydraulic power. Fig. 132 illustrates the process of pressing 



FIG. 131. Machined Commutator in Building Ring ready for Bush 



the V end rings on to the commutator under hydraulic pressure. 

 The bolts which hold the end rings together are tightened 

 at the same time, so that, when removed from the press, the 

 commutator is a rigid structure. With the increasing size of 

 commutators there is a general tendency to dispense with 

 hydraulic power for this process; but it is, nevertheless, of 

 advantage at any rate up to diameters of 2 feet or more 

 though the equipment is expensive. For a 30-inch diameter 



