Lester Allan Pelton - Hydroelectric Power

Pelton Wheel Turbine Powers Hydroelectric Power Production

Lester Pelton invented a type of free-jet water turbine called the Pelton Wheel or Pelton turbine. This turbine is used for hydroelectric power generation. It is one of the original green technologies, replacing coal or wood with the power of falling water.

Lester Pelton and the Pelton Water Wheel Turbine


Pelton made his living as a carpenter and a millwright.

At that time there was a great demand for new power sources to run the machinery and mills necessary for the expanding gold mines. Many mines depended on steam engines, but those required exhaustible supplies of wood or coal. What was abundant was water power from the fast running mountain creeks and waterfalls.

Waterwheels that had been used to power flour mills worked best on larger rivers and did not work well in the faster moving and less voluminous mountain creeks and waterfalls. What worked were the newer water turbines that used wheels with cups rather than flat panels.  A landmark design in water turbines was the highly efficient Pelton Wheel.

W. F. Durand of Stanford University wrote in 1939 that Pelton made his discovery when he observed a misaligned water turbine where the jet of water hit the cups near the edge rather than the middle of the cup.

The turbine moved faster. Pelton incorporated this into his design, with a wedge-shaped divider in the middle of a double cup, splitting the jet. Now the water being ejected from both halves of the split cups act to propel the wheel faster. He tested his designs in 1877 and 1878, getting a patent in 1880.



Pelton wheels were used to provide electrical power at hydroelectric facilities around the world. One in Nevada City had an output of 18000 horsepowers of electricity for 60 years. The largest units can produce over 400 megawatts.







