. Journal of electricity. AN IDAHO INSTALLATIONDouble discharge Francis turbine. 440 ft. head, 8500 horsepower, 300 revolutions per minute. Two built in1907 for Telluride Power Company, Bear River Plant, Idaho 158 JOURNAL OF ELECTRICITY [Vol. 40—No. 3 of an impulse wheel decreases as the head increases, andalso as the capacity increases. We thus approach conditionswhere the design of a Francis turbine becomes impracticalbecause of uncommercially high speed of the generator fora given capacity, or because of too great capacity for com-mercial speed. Similarly, conditions will be found where the
. Journal of electricity. AN IDAHO INSTALLATIONDouble discharge Francis turbine. 440 ft. head, 8500 horsepower, 300 revolutions per minute. Two built in1907 for Telluride Power Company, Bear River Plant, Idaho 158 JOURNAL OF ELECTRICITY [Vol. 40—No. 3 of an impulse wheel decreases as the head increases, andalso as the capacity increases. We thus approach conditionswhere the design of a Francis turbine becomes impracticalbecause of uncommercially high speed of the generator fora given capacity, or because of too great capacity for com-mercial speed. Similarly, conditions will be found where the design ofan impulse wheel (even with a multiple arrangement of jets)becomes impractical, because of uncommercially low speed. Single discharge overhung Francis turbine, 450 ft. head, 7000 horse-power, 450 revolutions per minute. Three built in 1911, for North-ern California Power Company, Coleman Plant, California. for a given capacity, or because of too small capacity for acommercial speed. Prom the above it follows that the practical limits ofapplication of an impulse wheel in the direction of the lowerheads is pretty well fixed, whereas the limits of application ofthe Francis turbine in the direction of the higher heads tosome extent permits of greater and greater development asthe required capacity of the unit is increased, and as the loadconditions of such a generating unit permit of operation at acontinuously fair gate-opening, or load factor. Aside from the question of correct design of a high-headFrancis turbine runner, from the point of view of hydraulicwear and tear, the problem of properly taking care of the endthrust was one which greatly impeded the application of thesingle discharge type of tur
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Keywords: ., bookcentury1900, bookdecade1910, bookidjo, booksubjectelectricity
