Hydraulic Turbine Efficiencies: High Specific Speed Hydraulic Turbines in Their Bearing on the Proportioning of the Number of Units in Low-Head Hydro-Electric Plants

The writer will indicate briefly the comparative efficiencies which can be obtained by using medium-speed wheels (of which the specific speed, N_s, is equal to about 75) and high-spee d wheels (N_s equal to about 175). The efficiencies shown throughout this paper are based on model runners of the size usually tested at the Holyoke flume, that is, about 39 sec-ft. discharge at 1-ft. head. Under good conditions, it is possible to obtain better results with larger wheels in place. The data and information contained herein are obtained from tests made in the Holyoke flume and in the specially designed and constructed testing flume of the S. Morgan Smith Company.