Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. The abbreviations AC and DC are often used to mean simply alternating and direct, respectively, as when they modify current or voltage.
George Westinghouse Jr. was an American entrepreneur and engineer based in Pennsylvania who created the railway air brake and was a pioneer of the electrical industry, receiving his first patent at the age of 19. Westinghouse saw the potential of using alternating current for electric power distribution in the early 1880s and put all his resources into developing and marketing it. This put Westinghouse's business in direct competition with Thomas Edison, who marketed direct current for electric power distribution. In 1911 Westinghouse received the American Institute of Electrical Engineers's (AIEE) Edison Medal "For meritorious achievement in connection with the development of the alternating current system." He founded the Westinghouse Electric Corporation in 1886.
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or a supercapacitor. Locomotives with on-board fuelled prime movers, such as diesel engines or gas turbines, are classed as diesel-electric or gas turbine-electric and not as electric locomotives, because the electric generator/motor combination serves only as a power transmission system.
The utility frequency, (power) line frequency or mains frequency is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country.
The Ganz Machinery Works Holding is a Hungarian holding company. Its products are related to rail transport, power generation, and water supply, among other industries.
Southern California Edison (SCE), the largest subsidiary of Edison International, is the primary electric utility company for much of Southern California. It provides 15 million people with electricity across a service territory of approximately 50,000 square miles. However, the Los Angeles Department of Water and Power, San Diego Gas & Electric (SDG&E), Imperial Irrigation District, and some smaller municipal utilities serve substantial portions of the southern California territory. The northern part of the state is generally served by the Pacific Gas & Electric Company of San Francisco. Other investor-owned utilities (IOUs) in California include SDG&E, PacifiCorp, Bear Valley Electric, and Liberty Utilities.
John Samuel Eastwood was an American engineer who built the world's first reinforced concrete multiple-arch dam on bedrock foundation at Hume Lake, California, in 1908, and was one of California's pioneers of hydroelectric power production. Eastwood's papers are held at the Water Resources Collections and Archives, University of California, Riverside.
Folsom Powerhouse State Historic Park is a historical site preserving an 1895 alternating current (AC) hydroelectric power station—one of the first in the United States.
Dick, Kerr and Company was a locomotive and tramcar manufacturer based in Kilmarnock, Scotland and Preston, England.
Mill Creek is a 17.8-mile-long (28.6 km) stream, originating in the San Bernardino Mountains, in San Bernardino County, California. It is a major tributary of the Santa Ana River. Their confluence occurs just downstream of the upper Santa Ana Canyon mouth. Part of the upper creek flows through San Bernardino National Forest, with the headwaters, being in the San Gorgonio Wilderness.
The Ames Hydroelectric Generating Plant, constructed in 1890 near Ophir, Colorado, was one of the first commercial system to produce and transmit alternating current (AC) electricity for industrial use and one of the first AC hydro-electric plants ever constructed. It became operational in 1891 and was built by Westinghouse Electric around two of their large alternators. One was set up in the valley as a generator and driven by water. It was connected by a 2.6-mile (4.2 km) transmission line to the second alternator used as a motor up at the Gold King Mine to drive the mining operation. The facility has been changed and upgraded over the years but is still in operation. It is now on the List of IEEE Milestones.
Electric power transmission, the tools and means of moving electricity far from where it is generated, date back to the late 19th century. They include the movement of electricity in bulk and the delivery of electricity to individual customers ("distribution"). In the beginning, the two terms were used interchangeably.
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids consist of power stations, electrical substations to step voltage up or down, electric power transmission to carry power long distances, and lastly electric power distribution to individual customers, where voltage is stepped down again to the required service voltage(s). Electrical grids vary in size and can cover whole countries or continents. From small to large there are microgrids, wide area synchronous grids, and super grids.
Hydroelectricity is, as of 2019, the second-largest renewable source of energy in both generation and nominal capacity in the United States. In 2021, hydroelectric power produced 31.5% of the total renewable electricity, and 6.3% of the total U.S. electricity.
The Helms Pumped Storage Plant is located 50 mi (80 km) east of Fresno, California in the Sierra Nevada Mountain Range's Sierra National Forest. It is a power station that uses Helms Creek canyon on the North Fork of the Kings River for off-river water storage and the pumped-storage hydroelectric method to generate electricity. After being planned in the early 1970s, construction on the plant began in June 1977 and commercial operations began on 30 June 1984. It has an installed capacity of 1,212 MW and is owned by Pacific Gas and Electric Company.
The Big Creek Hydroelectric Project is an extensive hydroelectric power scheme on the upper San Joaquin River system, in the Sierra Nevada of central California. The project is owned and operated by Southern California Edison (SCE). The use and reuse of the waters of the San Joaquin River, its South Fork, and the namesake of the project, Big Creek – over a vertical drop of 6,200 ft (1,900 m) – have over the years inspired a nickname, "The Hardest Working Water in the World".
Single-phase generator is an alternating current electrical generator that produces a single, continuously alternating voltage. Single-phase generators can be used to generate power in single-phase electric power systems. However, polyphase generators are generally used to deliver power in three-phase distribution system and the current is converted to single-phase near the single-phase loads instead. Therefore, single-phase generators are found in applications that are most often used when the loads being driven are relatively light, and not connected to a three-phase distribution, for instance, portable engine-generators. Larger single-phase generators are also used in special applications such as single-phase traction power for railway electrification systems.
The Pomona Water Power Plant, built in 1892, was the first AC power plant in California. It fed electricity to the Pomona Valley, and was designated a California Historic Landmark (No.514) on November 25, 1953.
Louis Bell was an American engineer, physicist, inventor, and academic. He was an early pioneer in illumination engineering and the transmission of electricity, being awarded 25 patents in power transmission.
