Telluride in San Miguel County, Colorado — The American Mountains (Southwest)
A Milestone in the History of Alternating Current
| | Telluride Local History Series | |
Photographed by Cosmos Mariner, July 18, 2025
1. A Milestone in the History of Alternating Current Marker
In 1891 a simple 100 H.P. alternating current generator, housed in a small wooden shack at Ames near Telluride, began transmitting power to run the mill at the Gold King Mine, 2.6 miles away. It was the first long distance transmission of A.C. electric power for commercial purposes, and sparked the beginning of the electric power industry in the U.S.
By the late 1880's, escalating fuel and transportation costs were resulting in the early bankruptcy of many regional mines.
In response to the power requirements of the Gold King Mine, L. L. Nunn, local entrepreneur and newly appointed partner-in-charge of mine operations, contracted with George Westinghouse to build and supply an A.C. system to run the mills. The system, based on the design of Nikola Tesla and William Stanley, was assembled and tested through the spring of 1891. The stage was set for an historic event. In June of that year the switch was thrown, initiating an economic boom and a new era in mining. Other mines soon received A.C. power and, by 1894, L. L. Nunn extended his system into Telluride, making it the best lighted town in the land.
The Ames plant was
this page online
L.L. Nunn eventually expanded his power company from Colorado into Utah, Montana, Idaho and Wyoming. He went on to found an institution of higher education, the Telluride Association, which thrives today at Deep Springs, CA and at Cornell University.
Erected 1991 by Town of Telluride.
Topics. This historical marker is listed in these topic lists: Industry & Commerce • Science & Medicine. A significant historical date for this entry is June 19, 1891.
Location. 37° 56.253′ N, 107° 48.771′ W. Marker is in Telluride, Colorado, in San Miguel County. It is at the intersection of West Colorado Avenue and Oak Street (now a pedestrian walkway), on the right when traveling east on West Colorado Avenue. The marker is located beside the sidewalk, on the north side of Elks Park. Touch for map. Marker is at or near this postal address: 236 West Colorado Avenue, Telluride CO 81435, United States of America. Touch for directions.
Regionally, this marker is in the Western Slope. It is also in the American Mountain West, in Colorado Plateau, and at the
Arlene Reid Collection
2. Marker detail: L.L. Nunn
Other nearby markers. At least 8 other markers are within walking distance of this marker: New Sheridan Hotel (here, next to this marker); Telluride's Founding (here, next to this marker); Transportation (here, next to this marker); Telluride (a few steps from this marker); Courthouse (within shouting distance of this marker); Colorado Centennial Project (within shouting distance of this marker); a different marker also named New Sheridan Hotel (within shouting distance of this marker); Tomboy Mine Office (within shouting distance of this marker). Touch for a list and map of all markers in Telluride.
Also see . . .
1. Lucien Lucius Nunn (1853-1925) (Wikipedia).
Excerpt: In 1880, Nunn moved to Telluride, Colorado, where he started a law practice and dealt in real estate. By 1890 he had become involved in gold mining, journalism, and banking within the small community. In order to help his mining operations(Submitted on September 1, 2025, by Cosmos Mariner of Cape Canaveral, Florida.)prosper, and because of the extremely high cost of coal for steam power generation, Nunn persuaded George Westinghouse to engineer and help finance the worlds first A/C power plant used for industrial purposes (mining), the Ames Hydroelectric Generating Plant. This plant, built by George Westinghouse, became part of the Nunns Telluride Power Company which would later become part of Utah Power and Light. Nunn continued investing in the power industry and helped design the Ontario Power Plant in Niagara Falls, Ontario.Photographed by Cosmos Mariner, July 18, 20253. A Milestone in the History of Alternating Current MarkerLooking southwest; West Colorado Avenue is to the right. Elks Park is in the background.
2. Ames Hydroelectric Generating Plant (Wikipedia).
Excerpt: The need to power a stamp mill to process ore at the Gold King Mine up in the mountains near Ophir, Colorado drove major stockholder Lucien L. Nunn to seek a less expensive alternative to the wood powered steam mill at the site. Timber fuel was in scarce supply at the mines 12,000-foot height and coal could not be used because there was no railroad leading to the mine. The San Miguel River 3000 feet down the slope 3 miles from the mine looked to be a good power source. Lucien's brother Paul, an electrical engineer, began looking into using electric motors to drive the plant. A 220-volt direct current electric system was found to be too expensive due to the size of the copper conductors needed to transmit such a low voltage the distances they were contemplating. High voltage alternating current system looked more promising, so they contacted Pittsburgh, Pennsylvania based Westinghouse Electric in 1890 and convinced them to supply an electricity driven system based on alternating current technology.(Submitted on September 1, 2025, by Cosmos Mariner of Cape Canaveral, Florida.)
In the summer of 1890 Westinghouse delivered the equipment and the engineers installed it later that winter. The system consisted of two identical 100-hp Westinghouse single-phase alternators (the largest the company made at the time). One was set up in a generator house, initially just a wooden shed, in the small settlement of Ames where the Howard Fork and Lake Fork streams joined to form the San Miguel River, just outside Ophir. Used as a generator, it produced 3000-volt, 133 Hertz, single-phase AC. The electricity was transmitted 2.6 miles up the mountain to the mine via two bare copper wires mounted on poles using Western Union cross-arms with insulators. At the mine the second 100-hp Westinghouse alternator was installed in the role of a synchronous AC motor to drive the stamping mill. The power system became operational on 19 June 1891.
Credits. This page was last revised on September 2, 2025. It was originally submitted on August 29, 2025, by Cosmos Mariner of Cape Canaveral, Florida. This page has been viewed 188 times since then and 73 times this year. Photos: 1, 2, 3. submitted on September 1, 2025, by Cosmos Mariner of Cape Canaveral, Florida.
