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Alternators
An alternator (or synchronous generator) is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature.Gordon R. Selmon, ''Magnetoelectric Devices'', John Wiley and Sons, 1966 no ISBN pp. 391-393 Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In principle, any AC electrical generator can be called an alternator, but usually, the term refers to small rotating machines driven by automotive and other internal combustion engines. An alternator that uses a permanent magnet for its magnetic field is called a magneto. Alternators in power stations driven by steam turbines are called turbo-alternators. Large 50 or 60 Hz three-phase alternators in power plants generate most of the world's electric power, which is distributed by electric power grids. History Alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexanderson Alternator
An Alexanderson alternator is a rotating machine, developed by Ernst Alexanderson beginning in 1904, for the generation of high-frequency alternating current for use as a radio transmitter. It was one of the first devices capable of generating the continuous radio waves needed for transmission of amplitude modulated (AM) signals by radio. It was used from about 1910 in a few "superpower" longwave radiotelegraphy stations to transmit transoceanic message traffic by Morse code to similar stations all over the world. Although superseded in the early 1920s by the development of vacuum-tube transmitters, the Alexanderson alternator continued to be used until World War II. It is on the list of IEEE Milestones as a key achievement in electrical engineering. History Prior developments After radio waves were discovered in 1887, the first generation of radio transmitters, the spark gap transmitters, produced strings of '' damped waves'', pulses of radio waves which died out to ze ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Alternator
A linear alternator is an electromechanical type of alternator that is essentially a linear motor used as an electrical generator. An alternator is a type of alternating current (AC) electrical generator. The devices are often physically equivalent. The principal difference is in how they are used and which direction the energy flows. An alternator converts mechanical energy to electrical energy, whereas a motor converts electrical energy to mechanical energy. Like many electric motors and electric generators, the linear alternator works by the principle of electromagnetic induction. However, most alternators work with rotary motion, whereas ''linear'' alternators work with ''linear'' motion (i.e. motion in a straight line). Moving-magnet linear alternators are integral parts of thermoacoustic power converters. Theory A linear alternator is most commonly used to convert back-and-forth motion directly into electrical energy. This eliminates the need for a crank or linkage to conv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-phase
Three-phase electric power (abbreviated 3ϕ) is a common type of alternating current (AC) used in electricity generation, Electric power transmission, transmission, and Electric power distribution, distribution. It is a type of polyphase system employing three wires (or four including an optional neutral return wire) and is the most common method used by electrical grids worldwide to transfer power. Three-phase electrical power was developed in the 1880s by several people. In three-phase power, the voltage on each wire is 120 degrees phase shifted relative to each of the other wires. Because it is an AC system, it allows the voltages to be easily stepped up using transformers to high voltage for transmission and back down for distribution, giving high efficiency. A three-wire three-phase circuit is usually more economical than an equivalent two-wire Single-phase electric power, single-phase circuit at the same line-to-ground voltage because it uses less conductor material to tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow through semiconductors, electrical insulation, insulators, or even through a vacuum as in electron beam, electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A archaism, term formerly used for this type of current was galvanic current. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', as when they modify ''Electric current, current'' or ''voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains Electronics, electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphase System
A polyphase system (the term coined by Silvanus Thompson) is a means of distributing alternating-current (AC) electrical power that utilizes more than one AC phase, which refers to the phase offset value (in degrees) between AC in multiple conducting wires; ''phases'' may also refer to the corresponding terminals and conductors, as in color codes. Polyphase systems have two or more energized electrical conductors carrying alternating currents with a defined phase between the voltage waves in each conductor. Early systems used 4 wire two-phase with a 90° phase angle, but modern systems almost universally use three-phase voltage, with a phase angle of 120° (or 2π/3 radians). Polyphase systems are particularly useful for transmitting power to electric motors which rely on alternating current to rotate. Three-phase power is used for industrial applications and for power transmission. Compared to a single-phase, two-wire system, a three-phase three-wire system transmits thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transformer
In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, 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, 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 Alternating current, 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 signa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC Press
The CRC Press, LLC is an American publishing group that specializes in producing technical books. Many of their books relate to engineering, science and mathematics. Their scope also includes books on business, forensics and information technology. CRC Press is now a division of Taylor & Francis, itself a subsidiary of Informa. History The CRC Press was founded as the Chemical Rubber Company (CRC) in 1903 by brothers Arthur, Leo and Emanuel Friedman in Cleveland, Ohio, based on an earlier enterprise by Arthur, who had begun selling rubber laboratory aprons in 1900. The company gradually expanded to include sales of laboratory equipment to chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...s. In 1913 the CRC offered a short (116-page) manual called the ''Rubber Handboo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganz Works
The Ganz Machinery Works Holding is a Hungary, Hungarian holding company. Its products are related to rail transport, power generation, and water supply, among other industries. The original Ganz Works or Ganz ( or , ''Ganz companies'', formerly ''Ganz and Partner Iron Mill and Machine Factory'') operated between 1845 and 1949 in Budapest, Hungary. It was named after Ábrahám Ganz, the founder and manager of the company. Ganz is probably best known for the manufacture of tramcars, but was also a pioneer in the application of Three-phase AC railway electrification, three-phase alternating current to electric railways. Ganz also made ships (through its ''Ganz Danubius'' division), bridge steel structures (''Ganz Acélszerkezet'') and high-voltage equipment (''Ganz Transelektro''). In the early 20th century the company experienced its heyday and became the third-largest industrial enterprise in the Kingdom of Hungary after the ''Manfréd Weiss Steel and Metal Works'' and the ''MÁV ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yablochkov Candle
A Yablochkov candle (sometimes electric candle or Jablochkoff candle) is a type of electric carbon arc lamp, invented in 1876 by the Russian electrical engineer Pavel Yablochkov. Design A Yablochkov candle consists of a sandwich of two electrodes, which are long carbon rods, approximately 6 by 12 millimetres in cross-section, separated by a block of inert and insulating material such as plaster of Paris or kaolin. There is a small piece of fuse wire or carbon paste linking the two carbon rods at the top end. The assembly is mounted vertically into a suitable insulated holder. On application of the electric supply, the fuse wire "blows" and strikes the arc. The arc then continues to burn, gradually consuming the carbon electrodes and the intervening plaster, which melts at the same pace. The first candles were powered by a Gramme machine. The drawback of using direct current was that one of the rods would burn at twice the rate of the other. This problem was initially solved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arc Lamp
An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light. It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century. It continued in use in more specialized applications where a high intensity point light source was needed, such as searchlights and movie projectors until after World War II. The carbon arc lamp is now obsolete for most of these purposes, but it is still used as a source of high intensity ultraviolet light. The term is now used for gas discharge lamps, which produce light by an arc between metal electrodes through a gas in a glass bulb. The common fluorescent lamp is a low-pressure mercury arc lamp. The xenon arc lamp, which produces a high ... [...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), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, 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. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sebastian Ziani De Ferranti
Sebastian Pietro Innocenzo Adhemar Ziani de Ferranti (9 April 1864 – 13 January 1930) was a British electrical engineer and inventor who pioneered high-voltage AC power in the UK, patented the Ferranti dynamo and designed Deptford power station. Personal life Sebastian Ziani de Ferranti was born in Liverpool, England. His Italian father, Cesare, was a photographer (son of composer Marco Aurelio Zani de Ferranti) and his mother Juliana de Ferranti (née Scott) was a concert pianist. He was educated at Hampstead School, London; St. Augustine's College, Westgate-on-Sea; and University College London. He married Gertrude Ruth Ince on 24 April 1888 at St Dominic's Priory Hampstead and they had seven children: Zoë Vanda Marie (1889–1978); Basil (1891–1917); Gerard Vincent (1893–1980); Vera Catherine (1898–1993); Yolanda (1902–1919); Denis (1908–1992) and Yvonne Teresa (1913-1988). Ferranti died on 13 January 1930 in Zürich, Switzerland. He was buried at Hampst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
