Pelton wheel, c 1900.
© Science Museum / Science & Society Picture Library
Model (scale 1:5). The Pelton wheel was designed by the American mining engineer Lester Pelton (1829-1908) and was often used to produce electricity in hydroelectric power stations. Water held in a reservoir above the turbine is released and enters the turbine through two nozzles. It hits hemispherical cups arranged round the circumference of a wheel, causing the wheel to turn. This model shows a Pelton wheel connected to a generator - a very effective arrangement giving 80% efficiency over a wide range of loads.