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The Pelton wheel or Pelton Turbine is an impulse-type water turbine invented by American inventor Lester Allan Pelton in the 1870s. [ 1 ] [ 2 ] The Pelton wheel extracts energy from the impulse of moving water, as opposed to water's dead weight like the traditional overshot water wheel .
This allows accurate calculations to be made of the turbine's performance for a range of heads. Well-designed efficient machines typically use the following values: Impulse turbines have the lowest n s values, typically ranging from 1 to 10, a Pelton wheel is typically around 4, Francis turbines fall in the range of 10 to 100, while Kaplan ...
With the help of these equations the head developed by a pump and the head utilised by a turbine can be easily determined. As the name suggests these equations were formulated by Leonhard Euler in the eighteenth century. [1] These equations can be derived from the moment of momentum equation when applied for a pump or a turbine.
Kaplan turbine and electrical generator cut-away view. The runner of the small water turbine. A water turbine is a rotary machine that converts kinetic energy and potential energy of water into mechanical work. Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now, they are ...
Surprisingly, the turbine now moved faster. That was Pelton's great discovery. In other turbines the jet hit the middle of the cup and the splash of the impacting water wasted energy." [6] Experimenting and modelling, Pelton improved upon the efficiency of the Knight wheel (developed earlier by the Knight Foundry at nearby Sutter Creek).
The Pelton wheel turbine (better described as a radial turbine) translates the mechanical action of the Pelton wheel rotating in the liquid flow around an axis into a user-readable rate of flow (gpm, lpm, etc.). The Pelton wheel tends to have all the flow traveling around it with the inlet flow focused on the blades by a jet.
The peak efficiency of a cross-flow turbine is somewhat less than a Kaplan, Francis or Pelton turbine. However, the cross-flow turbine has a flat efficiency curve under varying load. With a split runner and turbine chamber, the turbine maintains its efficiency while the flow and load vary from 1/6 to the maximum.
At the rated power of 423 MW each turbine operates at a head of ~1869 meters (6130 feet) and a flow rate of 25 cubic meters per second, with an efficiency in excess of 92% (~92.23%). The turbine assembly is a five-jet configuration; the stream of each jet is 184.7 mm (7.2716535 inches) in diameter with an exit velocity of 191.5 meters/second ...