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121 Heaviside, Oliver
[br]b. 18 May 1850 London, Englandd. 2 February 1925 Torquay, Devon, England[br]English physicist who correctly predicted the existence of the ionosphere and its ability to reflect radio waves.[br]Brought up in poor, almost Dickensian, circumstances, at the age of 13 years Heaviside, a nephew by marriage of Sir Charles Wheatstone, went to Camden House Grammar School. There he won a medal for science, but he was forced to leave because his parents could not afford the fees. After a year of private study, he began his working life in Newcastle in 1870 as a telegraph operator for an Anglo-Dutch cable company, but he had to give up after only four years because of increasing deafness. He therefore proceeded to spend his time studying theoretical aspects of electrical transmission and communication, and moved to Devon with his parents in 1889. Because the operation of many electrical circuits involves transient phenomena, he found it necessary to develop what he called operational calculus (which was essentially a form of the Laplace transform calculus) in order to determine the response to sudden voltage and current changes. In 1893 he suggested that the distortion that occurred on long-distance telephone lines could be reduced by adding loading coils at regular intervals, thus creating a matched-transmission line. Between 1893 and 1912 he produced a series of writings on electromagnetic theory, in one of which, anticipating a conclusion of Einstein's special theory of relativity, he put forward the idea that the mass of an electric charge increases with its velocity. When it was found that despite the curvature of the earth it was possible to communicate over very great distances using radio signals in the so-called "short" wavebands, Heaviside suggested the presence of a conducting layer in the ionosphere that reflected the waves back to earth. Since a similar suggestion had been made almost at the same time by Arthur Kennelly of Harvard, this layer became known as the Kennelly-Heaviside layer.[br]Principal Honours and DistinctionsFRS 1891. Institution of Electrical Engineers Faraday Medal 1924. Honorary PhD Gottingen. Honorary Member of the American Association for the Advancement of Science.Bibliography1872. "A method for comparing electro-motive forces", English Mechanic (July).1873. Philosophical Magazine (February) (a paper on the use of the Wheatstone Bridge). 1889, Electromagnetic Waves.1892, Electrical Papers.1893–1912, Electromagnetic Theory.Further ReadingI.Catt (ed.), 1987, Oliver Heaviside, The Man, St Albans: CAM Publishing.P.J.Nahin, 1988, Oliver Heaviside, Sage in Solitude: The Life and Works of an Electrical Genius of the Victorian Age, Institute of Electrical and Electronics Engineers, New York.J.B.Hunt, The Maxwellians, Ithaca: Cornell University Press.See also: Appleton, Sir Edward VictorKF -
122 аппаратура для зарядки
Русско-английский военно-политический словарь > аппаратура для зарядки
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123 ток в оболочке кабеля
Русско-английский словарь по информационным технологиям > ток в оболочке кабеля
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124 защита от коротких замыканий
1. protection against short circuits2. protection against short curcuitsАвиация и космонавтика. Русско-английский словарь > защита от коротких замыканий
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125 короткое замыкание
завершение цикла; замыкание цепи — closing of the circuit
Авиация и космонавтика. Русско-английский словарь > короткое замыкание
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126 параллельная система ИБП
параллельная система ИБП
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[Интент]Parallel Operation: The system shall have the option to install up to four (4) UPSs in parallel configuration for redundancy or capacity.
1. The parallel UPS system shall be of the same design, voltage, and frequency. UPS modules of different size ratings shall be permitted to be paralleled together for purposes of increased capacity or UPS module redundancy. The UPSs in the parallel configuration shall not be required to have the same load capacity rating.
2. Parallel Capacity: With N+0 system-level redundancy, up to 2MW of load can be supported by the system.
3. Parallel Redundancy: With N+1 system-level redundancy, up to 1.5MW of load can be supported by the system, and only the UPS being replaced must be isolated from the source (bypass operation is not required for the entire system during the UPS replacement procedure).
4. Output control: A load sharing circuit shall be incorporated into the parallel control circuits to ensure that under no-load conditions, no circulating current exists between modules. This feature also allows each UPS to share equal amounts of the total critical load bus. The output voltage, output frequency, output phase angle, and output impedance of each module shall operate in uniformity to ensure correct load sharing. This control function shall not require any additional footprint and shall be an integral function of each UPS. The static bypass switches shall be connected in parallel.
5. Parallel System Controls: To avoid single points of failure, the UPS system shall have no single dedicated control system designed to control the operation of the parallel UPS system. Control of and direction of parallel UPSs shall take place via a master/slave relationship, where the first UPS to receive logic power asserts itself as a master. In the event of a master failure, a slave UPS shall take the role of master and assume the responsibility of the previous master UPS. Regardless of which UPS is master or slave, user changes to the system status, such as request for bypass, can be done from any UPS connected to the bus and all UPS on the bus shall transfer in simultaneously.
6. Communication: Communication between modules shall be connected so that the removal of any single cable shall not jeopardize the integrity of the parallel communication system. Load sharing communications shall be galvanically isolated for purposes of fault tolerance between UPS modules. A UPS module's influence over load sharing shall be inhibited in any mode where the UPS inverter is not supporting its output bus. Transfers to and from bypass can be initiated from any online UPS in the system.
7. Display: Each UPS multi-color LCD touch screen user interface shall be capable of using an active touch screen mimic bus to show the quantity of UPS(s) connected to the critical bus, as well as the general status of each UPS, such as circuit breaker status information. Any touchscreen display shall support the configuration of the [entire parallel] system and shall provide event and alarm data for all UPSs in the parallel configuration. A Virtual Display Application shall be available for download to the customer’s computer and shalll support remote monitoring of a complete system with up to 4 UPSs in parallel.
8. Battery runtime: Each UPS must have its own battery solution. The battery solution for the entire system can be a combination of standard and third-party batteries, but each UPS must use only one battery solution – either standard or third-party batteries.
9. Switchgear: A custom switchgear option shall be required for parallel operation.
[Schneider Electric]Тематики
EN
Русско-английский словарь нормативно-технической терминологии > параллельная система ИБП
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127 ячейка распределительного устройства
ячейка распределительного устройства
Часть распределительного устройства, содержащая всю или часть коммутационной и/или иной аппаратуры одного присоединения.
[ ГОСТ 24291-90]
Рис. ABB
Однолинейная схема ячейки распределительного устройства с двумя системами сборных шин
( Single line of a double busbar bay)1. Disconnector and earthing switch
1. Разъединитель-заземлитель
2. Circuit breaker
2. Выключатель
3. Current transformer
3. Трансформатор тока
4. Disconnector and earthing switch
4. Разъединитель-заземлитель
5. Voltage transformer
5. Трансформатор напряжения
6. Make-proof earthing switch
6. Быстродействующий заземлитель
7. Cable end unit
7. Кабельный модуль
Рис. ABB
Ячейка распределительного устройства с элегазовой изоляцией с двумя системами сборных шинТематики
- комплектное распред. устройство (КРУ)
EN
Русско-английский словарь нормативно-технической терминологии > ячейка распределительного устройства
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