Lester Allan Pelton (September 5, 1829 – March 14, 1908) was an American

inventor An invention is a unique or novel device, method, composition, idea, or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...

who contributed significantly to the development of

hydroelectricity Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

and

hydropower Hydropower (from Ancient Greek -, "water"), also known as water power or water energy, is the use of falling or fast-running water to Electricity generation, produce electricity or to power machines. This is achieved by energy transformation, ...

in the

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as well as world-wide. In the late 1870s, he invented the '' Pelton water wheel'', at that time the most efficient design of the impulse

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, t ...

. Recognized as one of the fathers of hydroelectric power, he was awarded the

Elliott Cresson Medal The Elliott Cresson Medal, also known as the Elliott Cresson Gold Medal, was the highest award given by the Franklin Institute. The award was established by Elliott Cresson, life member of the Franklin Institute, with $1,000 granted in 1848. Th ...

during his lifetime and is an inductee of the

National Inventors Hall of Fame The National Inventors Hall of Fame (NIHF) is an American not-for-profit organization, founded in 1973, which recognizes individual engineers and inventors who hold a US patent of significant technology. Besides the Hall of Fame, it also operate ...

Early life

Lester A. Pelton was born in a log-cabin in rural Vermilion Twp., Erie County, Ohio.Genealogy of the Pelton Family in America; 1892, by J.M. Pelton His grandfather, Captain Josiah Pelton, who lost most of his assets as a sea-captain during the War-of-1812 era, shortly later brought his family to Ohio. Lester's father was Allen Pelton, and his mother was Fanny Cuddeback, from another local early pioneer family. As a youngster, Lester worked on his family's farm and probably attended the nearby "Cuddeback" grade-school. In 1850, young Pelton, along with several other local males, emigrated from Ohio to participate in the

California gold rush The California gold rush (1848–1855) began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California from the rest of the U ...

. He was not successful as a gold-miner, but he fished the

Sacramento River The Sacramento River () is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River D ...

and sold his catch locally; and he worked in wood-milling and carpentry. In 1860, after the gold strikes in the nearby

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

he relocated to Camptonville—near the

Yuba River The Yuba River is a tributary of the Feather River in the Sierra Nevada and eastern Sacramento Valley, in the U.S. state of California. The main stem of the river is about long, and its headwaters are split into three major forks. The Yuba ...

and the California Mother Lode country—where he made his living as a

millwright A millwright is a craftsman or skilled tradesman who installs, dismantles, maintains, repairs, reassembles, and moves machinery in factories, power plants, and construction sites. The term ''millwright'' (also known as ''industrial mechanic'') ...

and

carpenter Carpentry is a skilled trade and a craft in which the primary work performed is the cutting, shaping and installation of building materials during the construction of buildings, ships, timber bridges, concrete formwork, etc. Carpenter ...

. Pelton spent much of his time reading and observing mining activity; his work and studies gained him critical knowledge of mining equipment and processes and related engineering principles.

Inventing the Pelton wheel

Pelton's ideas for improving the turbine water wheel came from his studies of mining equipment and operations in California's gold rush country. Summary descriptions of the local technology observed by Pelton, and of the science by which his turbine water wheel extracts kinetic energy from a coursing mountain stream follow... Steam-heat powered much of local mining activities but required a lot of wood for fuel; nearby forests were routinely decimated. Turbine

water wheel A water wheel is a machine for converting the kinetic energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wheel (usually constructed from wood or metal), with numerous b ...

s also were used to supply power, but these were inefficient in converting the kinetic energy of mountain streams to horsepower. D.P. Stern reports: "According to a 1939 article by W. F. Durand of Stanford University in Mechanical Engineering, Pelton's invention started from an accidental observation some time in the 1870s. Pelton was watching a spinning water turbine when the key holding its wheel onto its shaft slipped, causing it to become misaligned. Instead of the jet hitting the cups in their middle, the slippage made it hit near the edge; rather than the water flow being stopped, it was now deflected into a half-circle, coming out again with reversed direction. 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." Experimenting and modelling, Pelton improved upon the efficiency of the Knight wheel (developed earlier by the Knight Foundry at nearby Sutter Creek). The Knight wheel received the streamflow jet slightly off-center and at an angle into a ''single'' turbine cup. Alternatively, the Pelton wheel—by deploying a ''split double'' cup (in effect two cups side-by-side), then splitting the impinging water-jet directly onto the common vane of the double cup—captured a stream's kinetic energy more efficiently. There were two prime results of Pelton's design: it consolidated the introduction of a new physical science into the ancient human quest to develop hydropower, i.e., the science of the ''impulse'' turbine as opposed to the ''reaction'' turbine; and it revolutionized the use of turbines adapted for high

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

(i.e., elevation energy) sites. Before Pelton, almost all water turbines were reaction machines powered by water pressure, or

, while Pelton's wheel was powered by the

kinetic energy In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Rober ...

of a high

velocity Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector (geometry), vector Physical q ...

water-jet which could be conveniently developed from a small mountain stream.

Building the Pelton wheel

In the late 1870s Pelton modeled, tested and manufactured his first turbine wheel, dubbed the ''Pelton Runner''—later referring to the impulse blades only—at the Miners Foundry in

Nevada City, California Nevada City is the county seat of Nevada County, California, United States, northeast of Sacramento, California, Sacramento, southwest of Reno, Nevada, Reno and northeast of San Francisco. The population was 3,152 as of the 2020 United States ...

. In 1878, at the Mayflower Mine in Nevada City, he installed the first operational Pelton wheel. At that time the Knight Foundry wheel was being sold as the industry standard, but in a head-to-head competition staged in 1883 at the Idaho Mine in nearby Grass Valley, Pelton's design proved much more efficient. The Pelton design provided 90 percent efficiency (of converting streamflow kinetic energy to horsepower) while the next best competitor achieved less than 77 percent—at a time when most extant water wheels typically rated less than 40 percent. The Pelton wheel also provided sustained power during (typical) lowflow conditions in a mountain stream. In 1887 a miner attached Pelton's wheel to a

dynamo "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator. Dynamos employed electromagnets for self-starting by using residual magnetic field left in the iron cores ...

and produced the first

hydroelectric power Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

in the

. In 1895, the largest installation of Pelton's wheel during his lifetime was accomplished at the North Star Mine Powerhouse, Grass Valley, California, by the engineer Arthur De Wint Foote, who designed and installed an over-sized wheel of 30 feet diameter; it performed successfully, greatly increasing the hydropower delivered by the Pelton runners to produce compressed air for mining operations. Pelton

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

ed his wheel as well as his novel design of the double cup runner, and in 1888 formed the Pelton Water Wheel Company in San Francisco to supply the growing demand for hydropower and hydroelectricity throughout the West and world-wide. 'Pelton' is a trademark name for the products of that company, but the term is widely used generically for similar impulse turbines.

Death, legacy and awards

Pelton died in California at the age of seventy-eight and is interred at his family cemetery site in Vermilion, Ohio. His ''Pelton Runner'' design is still used to produce hydroelectric power in the United States and around the world, as shown here. Later designs such as the Turgo turbine, first patented in 1919, and the Banki turbine were inspired by the Pelton wheel. In 1895,

The Franklin Institute The Franklin Institute is a science museum and a center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin ...

Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...

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, awarded Lester Pelton the

, since renamed the Benjamin Franklin Medal, for Pelton's accomplishments of invention in technology. In 2006, he was

posthumously Posthumous may refer to: * Posthumous award, an award, prize or medal granted after the recipient's death * Posthumous publication, publishing of creative work after the author's death * Posthumous (album), ''Posthumous'' (album), by Warne Marsh, 1 ...

inducted into the National Inventors Hall of Fame in

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, formerly in Akron, Ohio. There are memorials and monuments celebrating Pelton and the ''Pelton Runner'' mounted in Camptonvlle, California, in the Miners Foundry in Nevada City, California, and at the

Smithsonian Museum The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, education and research centers, created by the U.S. government "for the increase and diffusion of knowledge". Founded on August 10, 1846, it operates as a trus ...

in Washington D.C., California Resort at

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, among other sites. In 1958, the actor William Hudson was cast as Pelton in the episode "Wheel of Fortune" on the syndicated television

anthology series An anthology series is a written series, radio, television, film, or video game series that presents a different story and a different set of characters in each different episode, season, segment, or short. These usually have a different ca ...

, ''

Death Valley Days ''Death Valley Days'' is an American Western (genre), Western anthology series featuring true accounts of the American Old West, particularly the Death Valley country of southeastern California. Created in 1930 by Ruth Woodman, the program was ...

'', hosted by Stanley Andrews. The episode focuses on Pelton's development of the principles of hydraulic mining.

References

External links