COMMUTATOR CONSTRUCTION 



111 



heavy steel ring, by hydraulic pressure, over the commutator, 

 making a very tight fit. This is more applicable to small standard 



MactuneA 



Surface Plate 



FIG, 125. Gauging. 



commutators, but has occasionally also been used for large com- 

 mutators, as shown in Fig. 128, which illustrates the assembling of 

 a 750 k.w. commutator by this method. Fig. 127 shows the 



jiifie. rina 



FIG. 126. Commutator Heating. 



segments assembled with their insulators, preparatory to pressing 

 on the ring, for which purpose they are temporarily bound up 

 with a few turns of stout wire, tape or rope. (Fig. 127 relates 

 to a 75.h.p. commutator.) 



