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Metadyne
A metadyne is a direct current electrical machine with two pairs of brushes. It can be used as an amplifier or rotary transformer. It is similar to a third brush dynamo but has additional regulator or "variator" windings. It is also similar to an amplidyne except that the latter has a compensating winding which fully counteracts the effect of the flux produced by the load current. The technical description is "a cross-field direct current machine designed to utilize armature reaction". A metadyne can convert a constant-voltage input into a constant-current, variable-voltage output. History The word ''metadyne'' is derived from the Greek words for conversion of power. While the name is believed to have been coined by Joseph Maximus Pestarini (Italian language Giuseppe Massimo Pestarini) in a paper which he submitted to the Montefiore International Contest at Liège, Belgium in 1928, the type of machine which it described had been known since the 1880s. The first known British pate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metadyne
A metadyne is a direct current electrical machine with two pairs of brushes. It can be used as an amplifier or rotary transformer. It is similar to a third brush dynamo but has additional regulator or "variator" windings. It is also similar to an amplidyne except that the latter has a compensating winding which fully counteracts the effect of the flux produced by the load current. The technical description is "a cross-field direct current machine designed to utilize armature reaction". A metadyne can convert a constant-voltage input into a constant-current, variable-voltage output. History The word ''metadyne'' is derived from the Greek words for conversion of power. While the name is believed to have been coined by Joseph Maximus Pestarini (Italian language Giuseppe Massimo Pestarini) in a paper which he submitted to the Montefiore International Contest at Liège, Belgium in 1928, the type of machine which it described had been known since the 1880s. The first known British pate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotary Transformer
A rotary (rotatory) transformer is a specialized transformer used to couple electrical signals between two parts that rotate in relation to each other. They may be either cylindrical or 'pancake' shaped. Slip rings can be used for the same purpose, but are subject to friction, wear, intermittent contact, and limitations on the rotational speed that can be accommodated without damage. Wear can be eliminated by using a pool of liquid mercury or liquid metal alloy instead of a solid ring contact, but the toxicity and slow corrosion of mercury are problematic, and very high rotational speeds are again difficult to achieve. A rotary transformer has none of these limitations. Rotary transformers are constructed by winding the primary and secondary windings into separate halves of a ''cup core''; these concentric halves face each other, with each half mounted to one of the rotating parts. Magnetic flux provides the coupling from one half of the cup core to the other across an air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Third Brush Dynamo
A third-brush dynamo was a type of dynamo, an electrical generator, formerly used for battery charging on motor vehicles. It was superseded, first by a two-brush dynamo equipped with an external voltage regulator, and later by an alternator. Construction As the name implies, the machine had three brushes in contact with the commutator. One was earthed to the frame of the vehicle and another was connected (through a reverse-current cut-out) to the live terminal of the vehicle's battery. The third was connected to the field winding of the dynamo. The other end of the field winding was connected to a switch which could be adjusted (by inserting or removing resistance) to give "low" or "high" charge. This switch was sometimes combined with the vehicle's light switch so that switching on the headlights simultaneously put the dynamo in high charge mode. Disadvantages The third-brush dynamo had the advantage of simplicity but, by modern standards, it gave poor voltage regulation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplidyne
An amplidyne is an obsolete electromechanical amplifier invented prior to World War II by Ernst Alexanderson. It consists of an electric motor driving a DC generator. The signal to be amplified is applied to the generator's field winding, and its output voltage is an amplified copy of the field current. The amplidyne was used in industry in high power servo and control systems, to amplify low power control signals to control powerful electric motors, for example. It is now mostly obsolete. How an amplidyne works An amplidyne comprises an electric motor which turns a generator on the same shaft. Unlike an ordinary motor-generator, the purpose of an amplidyne is not to generate a steady voltage but to generate a voltage proportional to an input current, to amplify the input in applications where high output power is required. The motor provides the power, turning the generator at a constant speed, and the signal to be amplified is applied to the generator's field winding. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arnold Tustin
Arnold Tustin, (16 July 1899 – 9 January 1994), was a British engineer, and Professor of Engineering at the University of Birmingham and at Imperial College London, who made important contributions to the development of control engineering and its application to electrical machines. Biography Tustin started working in 1914 at the age of 16 as an apprentice to the C. A. Parsons and Company, of Newcastle upon Tyne. He entered Armstrong College, later part of Newcastle University, in 1916, served in the Royal Engineers in World War I, and eventually received his Master degree in science in 1922. In 1922 he joined Metropolitan-Vickers (Metro-Vick) as a graduate trainee. In the early 1930s he worked for Metro-Vick in Russia for two years, advising and selling equipment to the government companies. Here, he wrote his first book on the design of electric motors, which was also translated into Russian. In the late 1930s and during World War II Tustin was working on the Metadyne con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplidyne
An amplidyne is an obsolete electromechanical amplifier invented prior to World War II by Ernst Alexanderson. It consists of an electric motor driving a DC generator. The signal to be amplified is applied to the generator's field winding, and its output voltage is an amplified copy of the field current. The amplidyne was used in industry in high power servo and control systems, to amplify low power control signals to control powerful electric motors, for example. It is now mostly obsolete. How an amplidyne works An amplidyne comprises an electric motor which turns a generator on the same shaft. Unlike an ordinary motor-generator, the purpose of an amplidyne is not to generate a steady voltage but to generate a voltage proportional to an input current, to amplify the input in applications where high output power is required. The motor provides the power, turning the generator at a constant speed, and the signal to be amplified is applied to the generator's field winding. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A 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 ''current'' or '' voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alternating current via an inverter. Direct current has many uses, from the charging of batteries to large power ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turin
Turin ( , Piedmontese: ; it, Torino ) is a city and an important business and cultural centre in Northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital from 1861 to 1865. The city is mainly on the western bank of the Po River, below its Susa Valley, and is surrounded by the western Alpine arch and Superga Hill. The population of the city proper is 847,287 (31 January 2022) while the population of the urban area is estimated by Eurostat to be 1.7 million inhabitants. The Turin metropolitan area is estimated by the OECD to have a population of 2.2 million. The city used to be a major European political centre. From 1563, it was the capital of the Duchy of Savoy, then of the Kingdom of Sardinia ruled by the House of Savoy, and the first capital of the Kingdom of Italy from 1861 to 1865. Turin is sometimes called "the cradle of Italian liberty" for having been the political and intellectual centre of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energy, digital industry, additive manufacturing and venture capital and finance, but has since divested from several areas, now primarily consisting of the first four segments. In 2020, GE ranked among the Fortune 500 as the 33rd largest firm in the United States by gross revenue. In 2011, GE ranked among the Fortune 20 as the 14th most profitable company, but later very severely underperformed the market (by about 75%) as its profitability collapsed. Two employees of GE – Irving Langmuir (1932) and Ivar Giaever (1973) – have been awarded the Nobel Prize. On November 9, 2021, the company announced it would divide itself into three investment-grade public companies. On July 18, 2022, GE unveiled the brand names of the companies it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Alexanderson
Ernst Frederick Werner Alexanderson (January 25, 1878 – May 14, 1975) was a Swedish-American electrical engineer, who was a pioneer in radio and television development. He invented the Alexanderson alternator, an early radio transmitter used between 1906 and the 1930s for longwave long distance radio transmission. Alexanderson also created the amplidyne, a direct current amplifier used during the Second World War for controlling anti-aircraft guns. Background Alexanderson was born in Uppsala, Sweden. He studied at the University of Lund (1896–97) and was educated at the Royal Institute of Technology in Stockholm and the Technische Hochschule in Berlin, Germany. He emigrated to the United States in 1902 and spent much of his life working for the General Electric and Radio Corporation of America. Engineering work Alexanderson designed the Alexanderson alternator, an early longwave radio transmitter, one of the first devices which could transmit modulated audio (sound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artillery
Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and led to heavy, fairly immobile siege engines. As technology improved, lighter, more mobile field artillery cannons developed for battlefield use. This development continues today; modern self-propelled artillery vehicles are highly mobile weapons of great versatility generally providing the largest share of an army's total firepower. Originally, the word "artillery" referred to any group of soldiers primarily armed with some form of manufactured weapon or armor. Since the introduction of gunpowder and cannon, "artillery" has largely meant cannons, and in contemporary usage, usually refers to shell-firing guns, howitzers, and mortars (collectively called ''barrel artillery'', ''cannon artillery'', ''gun artillery'', or - a layman t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetomotive Force
In physics, the magnetomotive force (mmf) is a quantity appearing in the equation for the magnetic flux in a magnetic circuit, often called Ohm's law for magnetic circuits. It is the property of certain substances or phenomena that give rise to magnetic fields: \mathcal = \Phi \mathcal , where is the magnetic flux and \mathcal is the reluctance of the circuit. It can be seen that the magnetomotive force plays a role in this equation analogous to the voltage in Ohm's law: , since it is the cause of magnetic flux in a magnetic circuit: # \mathcal = NI where is the number of turns in the coil and is the electric current through the circuit. # \mathcal = \Phi \mathcal where is the magnetic flux and \mathcal is the magnetic reluctance # \mathcal = HL where is the magnetizing force (the strength of the magnetizing field) and is the mean length of a solenoid or the circumference of a toroid. Units The SI unit of mmf is the ampere, the same as the unit of current (analogo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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