And we have a winner! You're not a Californian are you? Those of us that are all studied the Pelton wheel in California history classes.
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This particular Pelton wheel was used for hydro electric generation starting in 1928. This 12 foot diameter wheel developed 18,000hp at its design speed of 257rpm. Another local Clamper plaque, btw.
The Pelton wheel was invented by Lester Pelton not far from here in the 1870's and patented in 1880. Due to its high efficiency Pelton's design quickly replaced earlier lower efficiency water driven turbine designs and then steam engines that powered lifts in the local hard rock gold mines. At its design speed a Pelton wheel would extract neatly all of the energy from a focused steam of high pressure water. Originally manufactured at the local Miner's Foundry here in Nevada City, CA, production moved to San Francisco as demand increased.
Hoover Dam on the Colorado river used a Pelton wheel in the base of the dam to generate power during construction. It was still operating when we last toured the dam maybe 30 years ago.
Pelton wheels were manufatured until 1956.
My youngest sons won a high school physics design contest using the basic concepts of the Pelton wheel to put together a water powered generator that developed more current than the other entires. They used soup spoons from a thrift store as the Pelton buckets and a garden hose nozzle to focus the water from the physics lab sinks onto their version of Pelton's wheel.