Industrial Niagara 



construct thrust bearings to take up the whole of this strain, and 1894 

 a hydraulic balancing piston has been resorted to for supporting e ueur 

 it. This device is simply a circular piston fast on the vertical 

 turbine shaft, set in a vertical cyclinder. The supporting force 

 consists of hydraulic pressure admitted to the under side of the 

 piston. This pressure is derived simply from the water in the 

 penstock supplied to the turbine, and when the latter is working 

 under full gate — that is, is taking water to its full capacity — 

 the pressure in the penstock is decidedly less, just as the pressure 

 in a water pipe is partly relieved by the opening of a faucet. 

 This causes the supporting force on the under side of the piston 

 to materially decrease, and a thrust bearing — that is, a bearing 

 adapted to withstand either pressure or pull, so as to hold the 

 shaft against the tendency to end play — has to be resorted to 

 in order to take up the difference. As a matter of fact, the differ- 

 ence between the supporting force when the flow is a minimum 

 and that when the gate is wide open is about two tons in the 

 seventy-six. The way this is handled is to arrange the area of the 

 piston and the depth below the upper water level so that at mini- 

 mum flow the supporting pressure will be about one ton more than 

 the total weight, and at full gate about the same amount less. 

 At the normal rate of working there is very little to be taken up 

 by the thrust bearings. 



An idea of the magnitude of the proportions of the generators 

 may be gathered from the fact that the designers were limited 

 in the size of base plates that they could use by the inability of 

 the railways to transport, even by specially large and powerful 

 cars, pieces of proportions originally designed from the factories 

 to the falls. 



It is stated that, had it not been for the tariff restrictions 

 imposed on the importation of electrical machinery, the generators 

 would probably have been purchased abroad. As it was, they, 

 as well as the motors which will operate on their circuits, are the 

 work of a great Pittsburg company. In the case of the turbines 

 the design was by a Geneva firm, and the construction mainly 



953 



