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International Electrotechnical Exhibition
The 1891 International Electrotechnical Exhibition was held between 16 May and 19 October on the disused site of the three former ( Western Railway Stations) in Frankfurt am Main, Germany. The exhibition featured the first long-distance transmission of high-power, three-phase electric current, which was generated 175 km away at Lauffen am Neckar. As a result of this successful field trial, three-phase current became established for electrical transmission networks throughout the world. History The "Elektrotechnische Gesellschaft" (Electrotechnical Society) was founded in Frankfurt in 1881 with the aim of promoting electricity and, in particular, furthering research into its application for industry and technology. Three years later, some ten manufacturers of electrical equipment had set themselves up in the city. In around 1890, some of the enterprises were established which would later become major firms in Frankfurt: Hartmann & Braun, Staudt & Voigt (from 1891 Voigt & H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Station
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. Many power stations contain one or more generators, a rotating machine that converts mechanical power into three-phase electric power. The relative motion between a magnetic field and a conductor creates an electric current. The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity. Low-carbon power sources include nuclear power, and an increasing use of renewables such as solar, wind, geothermal, and hydroelectric. History In early 1871 Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry. In 1878, a hydroelectric power station was designed and built b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transformer
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force (EMF) across any other coils wound around the same core. Electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circuits. Faraday's law of induction, discovered in 1831, describes the induced voltage effect in any coil due to a changing magnetic flux encircled by the coil. Transformers are used to change AC voltage levels, such transformers being termed step-up or step-down type to increase or decrease voltage level, respectively. Transformers can also be used to provide galvanic isolation between circuits as well as to couple stages of signal-processing circuits. Since the invention of the first constant-potential transfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utility Frequency
The utility frequency, (power) line frequency (American English) or mains frequency (British English) 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. During the development of commercial electric power systems in the late-19th and early-20th centuries, many different frequencies (and voltages) had been used. Large investment in equipment at one frequency made standardization a slow process. However, as of the turn of the 21st century, places that now use the 50 Hz frequency tend to use 220–240 V, and those that now use 60 Hz tend to use 100–127 V. Both frequencies coexist today (Japan uses both) with no great technical reason to prefer one over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definition One volt is defined as the electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units ( m, kg, second, s, and ampere, A) as : \text = \frac = \frac = \frac. It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per current), or joules per coulomb (energy per charge), which is also equivalent to electronvolts per elementary charge: : \text = \tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horsepower
Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the mechanical horsepower (or imperial horsepower), which is about 745.7 watts, and the metric horsepower, which is approximately 735.5 watts. The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses. It was later expanded to include the output power of other types of piston engines, as well as turbines, electric motors and other machinery. The definition of the unit varied among geographical regions. Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on 1 January 2010, the use of horsepower in the EU is permitted only as a supplementary unit. History The development of the stea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolutions Per Minute
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionless unit equal to 1, which it refers to as a revolution, but does not define the revolution as a unit. It defines a unit of rotational frequency equal to s−1. The superseded standard ISO 80000-3:2006 did however state with reference to the unit name 'one', symbol '1', that "The special name revolution, symbol r, for this unit is widely used in specifications on rotating machines." The International System of Units (SI) does not recognize rpm as a unit, and defines the unit of frequency, Hz, as equal to s−1. :\begin 1~&\text &&=& 60~&\text \\ \frac~&\text &&=& 1~&\text \end A corresponding but distinct quantity for describing rotation is angular velocity, for which the SI unit is the ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bockenheim (Frankfurt Am Main)
Bockenheim is a quarter of Frankfurt, Germany. It was incorporated into Frankfurt on 1 April 1895 and is part of the ''Ortsbezirk Innenstadt II''. Bockenheim lies west of central Frankfurt and is the third largest district by population in Frankfurt after Sachsenhausen and the Nordend with approximately 42,000 inhabitants. Bockenheim is bordered by the Goethe University, the Senckenberg museum and the Frankfurt Trade Fair in the south. The Bockenheimer Depot was the central tram depot, built around 1900, which is now a theatre, a venue of the Städtische Bühnen Frankfurt. Bockenheim also houses the headquarters of the Deutsche Bundesbank The Deutsche Bundesbank (), literally "German Federal Bank", is the central bank of the Federal Republic of Germany and as such part of the European System of Central Banks (ESCB). Due to its strength and former size, the Bundesbank is the most .... References Districts of Frankfurt {{Hesse-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heilbronn
Heilbronn () is a List of cities and towns in Germany, city in northern Baden-Württemberg, Germany, surrounded by Heilbronn (district), Heilbronn District. With over 126,000 residents, it is the sixth-largest city in the state. From the late Middle Ages, it developed into an important trading centre. At the beginning of the 19th century, Heilbronn became one of the centres of early industrialisation in Württemberg. Heilbronn's old town was completely destroyed during the air raid of 4 December 1944 and rebuilt in the 1950s. Today Heilbronn is the economic centre of the Heilbronn-Franconia, Heilbronn-Franken region. Heilbronn is known for its wine industry and is nicknamed ''Käthchenstadt'', after Heinrich von Kleist's ''Das Käthchen von Heilbronn''. Geography Heilbronn is located in the northern corner of the Neckar Sedimentary basin, basin at the bottom of the Wartberg (Heilbronn), Wartberg (308 m). It occupies both banks of the Neckar, and the highest spot inside city limit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
War Of The Currents
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc lamp street lighting running on high-voltage alternating current (AC), and large-scale low-voltage direct current (DC) indoor incandescent lighting being marketed by Thomas Edison's company. In 1886, the Edison system was faced with new competition: an alternating current system initially introduced by George Westinghouse's company that used transformers to step down from a high voltage so AC could be used for indoor lighting. Using high voltage allowed an AC system to transmit power over longer distances from more efficient large central generating stations. As the use of AC spread rapidly with other companies deploying their own systems, the Edison Electric Light Company claimed in early 1888 that high voltages used in an alternating curr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Gold Mark
The German mark (german: Goldmark ; sign: ℳ) was the currency of the German Empire, which spanned from 1871 to 1918. The mark was paired with the minor unit of the pfennig (₰); 100 pfennigs were equivalent to 1 mark. The mark was on the gold standard from 1871–1914, but like most nations during World War I, the German Empire removed the gold backing in August 1914, and gold and silver coins ceased to circulate. After the fall of the Empire due to the November Revolution of 1918, the mark was succeeded by the Weimar Republic's mark, derisively referred to as the Papiermark ("Paper mark") due to hyperinflation in the Weimar Republic from 1918–1923. History The introduction of the German mark in 1873 was the culmination of decades-long efforts to unify the various currencies used by the German Confederation.pp 205-218 https://books.google.com/books?id=GrJCAAAAIAAJ&pg=PA205#v=onepage&q&f=false The Zollverein unified in 1838 the Prussian and South German currenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
