Niagara Falls 100.000-Hp. Development

Niagara Falls 1 00,000 Hp. Development [13 vane is held in a central position between the distributor plates with fixed and equal clearances on each end of the vane; consequently there is no friction and no wear between the ends of the vanes and the distributor plates. A stuffing box is provided about each vane stem and water is thereby prevented from flowing through the bronze bearings supporting the vane—a specially desir- able feature in that silt and sand which would tend to rapidly wear the main supporting journal is not carried between the surfaces by leakage. Levers are keyed to the vane stems and attached to the shifting ring through an adjustable connection and links having a cross-sectional area so proportioned as to fail before a guide vane or its stem is strained beyond its elastic limit should a guide-vane passage become obstructed. Heavy plate-steel wearing plates line the distributor plate at each end of the guide vanes. Wearing bush- ings are embodied on the upper and lower distributer plates opposite corresponding wearing rings placed on the upper crown plate and the lower band of the runner. Runner of One Casting The runner is of grey iron in one casting made by means of fitted cores and is bolted to a cast-iron hub which is keyed to the tapered end of the turbine shaft and held in place by ring, key and keeper. Either a taper connection as here used or a forged flange on the end of the shaft upon which the runner is mounted makes a good construction, but where a water bearing is used, with a bushing on the shaft, the construction here used is the better one, as it enables the bushing to be made solid and therefore of less thickness and results in the lower peripheral speed for a given unit. The diameter of the shaft at the turbine guide bearing is 28 in. The turbine guide bearing consists of lignum vitæc fitted into cast-iron blocks having the end grain of the lignum vitæ toward the shaft. The bearing of this unit is 5 ft. in length and is made in two parts for convenience in dismantling and ease of handling. The bearing is lubricated by water supplied from the head- race through fine strainers. Connection is also made to the city mains for use of filtered water during times when headrace water contains considerable silt and sand. A feature which distinguishes Unit No. 16 from the other units is the cast-iron pit liner forming the turbine pit and transmitting the weight of the generator through this pit liner directly to the speed ring and through the vanes of the speed ring to the foundation. From a mechanical and design standpoint the value of this barrel can hardly be overestimated, tying together as it does all the major elements in which forces originate and from which they have to be transmitted. Interalignment of main working elements, i.e., gen- erator, turbine and regulating cylinders, is permanently- insured regardless of the behavior of the surrounding concrete. The guide vanes of the turbine are controlled by means of water pressure on two pistons connecting to opposite sides of the shifting ring, inclosed by cylinders, mounted directly on the outside of the sup- porting barrel or pit liner. The mounting of the oper- ating cylinders on the outside of the pit liner is unique and affords a clean design of the pit, as it keeps the governor pipes outside of the turbine chamber. This feature of design enables the cover-plate of the turbine to be removed by merely removing the pistons and crossheads and without disturbing the cylinders and governor piping. An interesting feature of design is the governor equipment especially designed for this unit. The guide vanes are shaped to cause the smoothest flow from the sing to the runner and the position of the stems on FIGS. 13 AND 14—TWO NEW 37,500-HP. UNITS OF THE NIAGARA FALLS POWER COMPANY The units were built by different manufacturers (left, I. P. Morris wheel and Westinghouse generator ; right, Allis-Chalmers unit) under the same general specifications. Generators are rated at 32,500 kva., 12,000 volts, and the units operate at 150 r.p.m. under 214-ft. head. Two types of draft tubes are shown— the spreading draft tube and hydraucone.