-
1 условия окружающей среды
•Depending on the environmental conditions,...
Русско-английский научно-технический словарь переводчика > условия окружающей среды
-
2 явление электрической дуги
явление электрической дуги
-
[Интент]Параллельные тексты EN-RU
Electric arc phenomenon
The electric arc is a phenomenon which takes place as a consequence of a discharge which occurs when the voltage between two points exceeds the insulating strength limit of the interposed gas; then, in the presence of suitable conditions, a plasma is generated which carries the electric current till the opening of the protective device on the supply side.
Gases, which are good insulating means under normal conditions, may become current conductors in consequence of a change in their chemical-physical properties due to a temperature rise or to other external factors.
To understand how an electrical arc originates, reference can be made to what happens when a circuit opens or closes.
During the opening phase of an electric circuit the contacts of the protective device start to separate thus offering to the current a gradually decreasing section; therefore the current meets growing resistance with a consequent rise in the temperature.
As soon as the contacts start to separate, the voltage applied to the circuit exceeds the dielectric strength of the air, causing its perforation through a discharge.
The high temperature causes the ionization of the surrounding air which keeps the current circulating in the form of electrical arc. Besides thermal ionization, there is also an electron emission from the cathode due to the thermionic effect; the ions formed in the gas due to the very high temperature are accelerated by the electric field, strike the cathode, release energy in the collision thus causing a localized heating which generates electron emission.
The electrical arc lasts till the voltage at its ends supplies the energy sufficient to compensate for the quantity of heat dissipated and to maintain the suitable conditions of temperature. If the arc is elongated and cooled, the conditions necessary for its maintenance lack and it extinguishes.
Analogously, an arc can originate also as a consequence of a short-circuit between phases. A short-circuit is a low impedance connection between two conductors at different voltages.
The conducting element which constitutes the low impedance connection (e.g. a metallic tool forgotten on the busbars inside the enclosure, a wrong wiring or a body of an animal entered inside the enclosure), subject to the difference of potential is passed through by a current of generally high value, depending on the characteristics of the circuit.
The flow of the high fault current causes the overheating of the cables or of the circuit busbars, up to the melting of the conductors of lower section; as soon as the conductor melts, analogous conditions to those present during the circuit opening arise. At that point an arc starts which lasts either till the protective devices intervene or till the conditions necessary for its stability subsist.
The electric arc is characterized by an intense ionization of the gaseous means, by reduced drops of the anodic and cathodic voltage (10 V and 40 V respectively), by high or very high current density in the middle of the column (of the order of 102-103 up to 107 A/cm2), by very high temperatures (thousands of °C) always in the middle of the current column and – in low voltage - by a distance between the ends variable from some microns to some centimeters.
[ABB]Явление электрической дуги
Электрическая дуга между двумя электродами в газе представляет собой физическое явление, возникающее в тот момент, когда напряжения между двумя электродами превышает значение электрической прочности изоляции данного газа.
При наличии подходящих условий образуется плазма, по которой протекает электрический ток. Ток будет протекать до тех пор, пока на стороне электропитания не сработает защитное устройство.
Газы, являющиеся хорошим изолятором, при нормальных условиях, могут стать проводником в результате изменения их физико-химических свойств, которые могут произойти вследствие увеличения температуры или в результате воздействия каких-либо иных внешних факторов.
Для того чтобы понять механизм возникновения электрической дуги, следует рассмотреть, что происходит при размыкании или замыкании электрической цепи.
При размыкании электрической цепи контакты защитного устройства начинают расходиться, в результате чего постепенно уменьшается сечение контактной поверхности, через которую протекает ток.
Сопротивление электрической цепи возрастает, что приводит к увеличению температуры.
Как только контакты начнут отходить один от другого, приложенное напряжение превысит электрическую прочность воздуха, что вызовет электрический пробой.
Высокая температура приведет к ионизации воздуха, которая обеспечит протекание электрического тока по проводнику, представляющему собой электрическую дугу. Кроме термической ионизации молекул воздуха происходит также эмиссия электронов с катода, вызванная термоэлектронным эффектом. Образующиеся под воздействием очень высокой температуры ионы ускоряются в электрическом поле и бомбардируют катод. Высвобождающаяся, в результате столкновения энергия, вызывает локальный нагрев, который, в свою очередь, приводит к эмиссии электронов.
Электрическая дуга длится до тех пор, пока напряжение на ее концах обеспечивает поступление энергии, достаточной для компенсации выделяющегося тепла и для сохранения условий поддержания высокой температуры. Если дуга вытягивается и охлаждается, то условия, необходимые для ее поддержания, исчезают и дуга гаснет.
Аналогичным образом возникает дуга в результате короткого замыкания электрической цепи. Короткое замыкание представляет собой низкоомное соединение двух проводников, находящихся под разными потенциалами.
Проводящий элемент с малым сопротивлением, например, металлический инструмент, забытый на шинах внутри комплектного устройства, ошибка в электромонтаже или тело животного, случайно попавшего в комплектное устройство, может соединить элементы, находящиеся под разными потенциалами, в результате чего через низкоомное соединение потечет электрический ток, значение которого определяется параметрами образовавшейся короткозамкнутой цепи.
Протекание большого тока короткого замыкания вызывает перегрев кабелей или шин, который может привести к расплавлению проводников с меньшим сечением. Как только проводник расплавится, возникает ситуация, аналогичная размыканию электрической цепи. Т. е. в момент размыкания возникает дуга, которая длится либо до срабатывания защитного устройства, либо до тех пор, пока существуют условия, обеспечивающие её стабильность.
Электрическая дуга характеризуется интенсивной ионизацией газов, что приводит к падению анодного и катодного напряжений (на 10 и 40 В соответственно), высокой или очень высокой плотностью тока в середине плазменного шнура (от 102-103 до 107 А/см2), очень высокой температурой (сотни градусов Цельсия) всегда в середине плазменного шнура и низкому падению напряжения при расстоянии между концами дуги от нескольких микрон до нескольких сантиметров.
[Перевод Интент]Тематики
- НКУ (шкафы, пульты,...)
EN
Русско-английский словарь нормативно-технической терминологии > явление электрической дуги
-
3 длительный допустимый ток
(длительный) допустимый ток
Максимальное значение электрического тока, который может протекать длительно по проводнику, устройству или аппарату при определенных условиях без превышения определенного значения их температуры в установившемся режиме
[ ГОСТ Р МЭК 60050-826-2009]
Этот ток обозначают IZ
[ ГОСТ Р 50571. 1-2009 ( МЭК 60364-1: 2005)]EN
(continuous) current-carrying capacity
ampacity (US)
maximum value of electric current which can be carried continuously by a conductor, a device or an apparatus, under specified conditions without its steady-state temperature exceeding a specified value
[IEV number 826-11-13]
ampacity
The current in amperes that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
[National Electrical Cod]FR
courant (permanent) admissible, m
valeur maximale du courant électrique qui peut parcourir en permanence, un conducteur, un dispositif ou un appareil, sans que sa température de régime permanent, dans des conditions données, soit supérieure à la valeur spécifiée
[IEV number 826-11-13]Ampacity, the term is defined as the maximum amount of current a cable can carry before sustaining immediate or progressive deterioration. Also described as current rating or current-carrying capacity, is the RMS electric current which a device can continuously carry while remaining within its temperature rating. The ampacity of a cable depends on:
- its insulation temperature rating;
- conductor electrical properties for current;
- frequency, in the case of alternating currents;
- ability to dissipate heat, which depends on cable geometry and its surroundings;
- ambient temperature.
Electric wires have some resistance, and electric current flowing through them causes voltage drop and power dissipation, which heats the cable. Copper or aluminum can conduct a large amount of current before melting, but long before the conductors melt, their insulation would be damaged by the heat.
The ampacity for a power cable is thus based on physical and electrical properties of the material & construction of the conductor and of its insulation, ambient temperature, and environmental conditions adjacent to the cable. Having a large overall surface area may dissipate heat well if the environment can absorb the heat.
In a long run of cable, different conditions govern, and installation regulations normally specify that the most severe condition along the run governs the cable's rating. Cables run in wet or oily locations may carry a lower temperature rating than in a dry installation. Derating is necessary for multiple circuits in close proximity. When multiple cables are near, each contributes heat to the others and diminishes the amount of cooling air that can flow past the individual cables. The overall ampacity of the insulated conductors in a bundle of more than 3 must be derated, whether in a raceway or cable. Usually the de-rating factor is tabulated in a nation's wiring regulations.
Depending on the type of insulating material, common maximum allowable temperatures at the surface of the conductor are 60, 75 and 90 degrees Celsius, often with an ambient air temperature of 30°C. In the U.S., 105°C is allowed with ambient of 40°C, for larger power cables, especially those operating at more than 2 kV. Likewise, specific insulations are rated 150, 200 or 250°C.
The allowed current in cables generally needs to be decreased (derated) when the cable is covered with fireproofing material.
For example, the United States National Electric Code, Table 310-16, specifies that up to three 8 AWG copper wires having a common insulating material (THWN) in a raceway, cable, or direct burial has an ampacity of 50 A when the ambient air is 30°C, the conductor surface temperature allowed to be 75°C. A single insulated conductor in air has 70 A rating.
Ampacity rating is normally for continuous current, and short periods of overcurrent occur without harm in most cabling systems. The acceptable magnitude and duration of overcurrent is a more complex topic than ampacity.
When designing an electrical system, one will normally need to know the current rating for the following:- Wires
- Printed Circuit Board traces, where included
- Fuses
- Circuit breakers
- All or nearly all components used
Some devices are limited by power rating, and when this power rating occurs below their current limit, it is not necessary to know the current limit to design a system. A common example of this is lightbulb holders.
[http://en.wikipedia.org/wiki/Ampacity]
Тематики
- электротехника, основные понятия
Синонимы
EN
DE
- Dauerstrombelastbarkeit, f
- Strombelastbarkeit, f
FR
- courant admissible, m
- courant permanent admissible, m
Русско-английский словарь нормативно-технической терминологии > длительный допустимый ток
-
4 в зависимости от
•The critical temperature varies with (or according to) the carbon content of the steel.
•Speeds up to 100 rpm are used in accordance with the size of pump.
•Different approaches are used depending (up)on the number of variables.
•The capacity may be varied to suit changing needs.
•The ratio of hydrogen varies with the manufacturing process.
II•Roll load against (or versus, or vs., or as a function of) strip thickness...
•The pressure- versus-flowrate curve...
•To describe the distribution of organisms in relation to their physical and biotic environments...
•The plot shows the energy in relation to the distance between the molecules.
* * *В зависимости от -- depending on, according to, with (в соответствии с); against, versus, vs, as a function of (в функции); in terms of (в плане), as + (needed, appropriate и т. п.)Depending on the operating conditions, 100 to 200 mg were sublimed.Since waterwall steam quality varies with firing rate, lumped average thermal capacitance changes with load.Steam cycle efficiency is shown against gas inlet temperature in Fig.Reynolds number at transition based on momentum thickness versus Pohlhausen parameter.Figure (...) shows the changes of Gibbs free energy in various reactions vs the temperature.The results are plotted in the form of local Stanton number as a function of position on the plate.The bonding between dissimilar metals has been discussed in terms of mutual solubility.Русско-английский научно-технический словарь переводчика > в зависимости от
-
5 источник питания постоянного напряжения и постоянного тока
- constant voltage/constant current power supply
источник питания постоянного напряжения и постоянного тока
-
[IEV number 313-04-03]EN
constant voltage/constant current power supply
power supply which operates as a constant voltage or a constant current power supply, depending on load conditions
Source: 551-19-06
[IEV number 313-04-03]FR
alimentation stabilisée en tension/courant
alimentation qui stabilise soit en tension soit en courant, en fonction des conditions de charge
Source: 551-19-06
[IEV number 313-04-03]Тематики
EN
- constant voltage/constant current power supply
DE
FR
- alimentation stabilisée en tension/courant
Русско-английский словарь нормативно-технической терминологии > источник питания постоянного напряжения и постоянного тока
-
6 в соответствии с
. в зависимости от; изменяться в соответствии с кривой; классификация по; находиться в соответствии с; согласно; соответствие•In line with this assumption, we have devised a model of...
•To modify the beach profile in response to changing wave conditions...
•Evaporators for marine use are classed as horizontal or vertical by (or according to, or depending on) the position of their tubes.
•The test report is performed in accord( ance) (or conformity, or compliance) with the specifications.
•In keeping with the limitation of only four orbitals, the formation of double or triple bonds between atoms of these elements reduces the coordination number of the central atom.
•The machine is designed and built to higher standards of accuracy.
•The sketch can be interpreted in terms of either system.
•The console pressure can be regulated to match the individual gauge range.
•In the reactors designed around this approach the energy-carrying neutrons released by thermonuclear reactions will be absorbed in a lithium blanket.
•These techniques must be selected in relation to the properties of the substances being separated.
* * *В соответствии с (нормами)The specimens were tested at a frequency of approximately 130 Hz, following ASTM E466 [...].В соответствии с -- in accordance with, in agreement with, in keeping with, in line with, in compliance with, consistent with; as required by, to match, following, according to; in step with (синхронно); per (в инструкциях); to conform to (о требованиях стандарта и т. п.), pursuant to (в письмах)Fatigue life results of the bearings tested were statistically analyzed in accordance with the methods of [...].In agreement with this, it was found that the low ф machine went into a part-span stall.Also, in keeping with practice, the inter-plate spacing was made equal to the plate length.The section on low-pressure heating boilers now had testing and marking requirements in line with those of the power boiler section.(Tf -- Ts) is kept fixed by increasing Ts with time as required by the surface temperature, Ts.Normally, this value of radial clearance is established to match the bearing size.According to a previous investigation of dressing [...], fracture can occur within the grain.The Sh number increases in step with the wake turbulence.Install housing and grease per figure and table.They are metered by orifice plate assemblies built to conform to BS 1042.Pursuant to your request, I am confirming our consent to the publication of the book in two volumes.Floating roof tanks generally do not require protection when installed in compliance with Section...Русско-английский научно-технический словарь переводчика > в соответствии с
-
7 в соответствии с
. в зависимости от; изменяться в соответствии с кривой; классификация по; находиться в соответствии с; согласно; соответствие•In line with this assumption, we have devised a model of...
•To modify the beach profile in response to changing wave conditions...
•Evaporators for marine use are classed as horizontal or vertical by (or according to, or depending on) the position of their tubes.
•The test report is performed in accord( ance) (or conformity, or compliance) with the specifications.
•In keeping with the limitation of only four orbitals, the formation of double or triple bonds between atoms of these elements reduces the coordination number of the central atom.
•The machine is designed and built to higher standards of accuracy.
•The sketch can be interpreted in terms of either system.
•The console pressure can be regulated to match the individual gauge range.
•In the reactors designed around this approach the energy-carrying neutrons released by thermonuclear reactions will be absorbed in a lithium blanket.
•These techniques must be selected in relation to the properties of the substances being separated.
Русско-английский научно-технический словарь переводчика > в соответствии с
-
8 в зависимости от полевых условий
General subject: depending on field conditionsУниверсальный русско-английский словарь > в зависимости от полевых условий
-
9 коэффициент приведённой длины
Construction: effective length factor (сжатого элемента), end condition factor, factor depending on the end conditions (элемента, работающего на продольный изгиб)Универсальный русско-английский словарь > коэффициент приведённой длины
-
10 изменяться
•Under these conditions, the braking distance could be considerably affected.
•As distillation continues, the distillate will continuously change in composition.
•When the intermolecular distance is changed (or altered),...
•The observer's notions as to... have undergone a change.
* * *Изменяться (вдвое)-- Growth rate varied as much as a factor of two. Изменяться -- to vary, to differ; to range (в диапазоне); to be modulated; to be graded (постепенно); to be affected (обычно ухудшаться); to reverse (на противоположное)Air flow is modulated with hand-operated valves.The mesh was graded in the horizontal direction to provide increased resolution near the vertical boundaries.NO emissions were not significantly affected when residual oil was fired. (... при сжигании мазута не изменялись существенно)Изменяться (по...) от... до-- The coatings vary in total penetrations from 0.05 mm to 0.23 mm after 2000 hr. (... глубина повреждения покрытий изменяется от...) Изменяться в... раз-- С is an empirical factor which can vary by a factor of five depending on material. Изменяться от... доSurface roughness values ranged from 3.1 mm for the chromium sesquioxide to 14.1 mm for tungsten carbide.In the tests cited, m varied (or: went) from 2.1 to 3.0.He suggested that N in equation (4) should be varied between three and zero as bubble size is increased.Изменяться от... кThese tools vary from manufacturer to manufacturer but some common observations may be made.The static weight of the person on the seat was assumed to be constant, but in practice it was likely to have varied slightly between the seats.Изменяться с-- The point of reattachment varies with time.Русско-английский научно-технический словарь переводчика > изменяться
-
11 конкретный
•Let us take the specific case of the Earth and the Moon.
•With the particular (or specific) construction shown in Fig. 16, air filters are always supplied.
•The maximum rate of change of a particular characteristic of the orbit...
•The expansion should be allowed for in the die design for each specific (or concrete) application.
* * *Конкретный -- particular, specific, individualThe location of the particular point under consideration was also non-dimensionalized with respect to the nozzle diameter.Points representing one specific type of compressor are connected by dotted lines.The NDTT can be increased rather dramatically in some cases, depending upon the individual alloy and irradiation conditions.Русско-английский научно-технический словарь переводчика > конкретный
-
12 длительность которого составляла
Длительность которого составляла-- During the run, the duration of which extended from 15 to 45 minutes depending on the operating conditions, periodic readings were made of the temperature.Русско-английский научно-технический словарь переводчика > длительность которого составляла
-
13 оказывать влияние
Оказывать влияние - to have an effect, to have an influence, to exert an effect, to exert an influence, to bear influence, to be influential, to produce an impact; to be a contribution (как констатация факта)Processing procedures which may be influential in the film composition include the substrate finishing and the film curing.The presence of the extractive probe produced an impact on the optically measured data rate that ranged from a small to a substantial effect depending on the operating conditions.The improvement in overall performance cannot be attributed entirely to the novel tip section shape, but it is thought to be a contribution.Русско-английский научно-технический словарь переводчика > оказывать влияние
-
14 национальный Олимпийский фотопул
национальный Олимпийский фотопул
Принимая во внимание потребности страны-организатора МОК может разрешить создание национального пула фотографов. В этом случае МОК и ОКОИ совместно с партнерами определяют правила работы национального Олимпийского фотопула и его статус по отношению к фотографам IOPP. Основной обязанностью национального фотопула является ведение подробной фотохроники выступлений спортсменов страны-организатора и распространение полученных изображений среди отечественных СМИ.
[Департамент лингвистических услуг Оргкомитета «Сочи 2014». Глоссарий терминов]EN
national Olympic photo pool (NOPP)
Depending on the conditions in the host country, the IOC may authorize the creation of a national photo pool. Where the National Olympic photo pool is established, the IOC and the OCOG will define with the partners concerned, the framework for its activity and its precise relationship with the IOPP. A prime responsibility of a national pool would be to ensure a comprehensive photographic coverage and national distribution of the host nation’s athletes to the host nation’s media organizations.
[Департамент лингвистических услуг Оргкомитета «Сочи 2014». Глоссарий терминов]Тематики
EN
Русско-английский словарь нормативно-технической терминологии > национальный Олимпийский фотопул
-
15 отсек шин
шинный отсек (распределительного устройства)
—
[Я.Н.Лугинский, М.С.Фези-Жилинская, Ю.С.Кабиров. Англо-русский словарь по электротехнике и электроэнергетике, Москва, 1999 г.]
отсек шин
-
[Интент]Параллельные тексты EN-RU
Рис. ABB
Busbar compartment
The busbar compartment is located in the middle section of the switchgear.
The main busbars can be located at the top, in the centre or at the bottom of the panel depending on the selected design and they distribute power to the various switchgear units; in some of the existing configurations the main busbars can be directly connected to and supply the circuit-breakers.
The distribution busbars are positioned vertically in the column and feed the panel circuit-breakers.
The busbar system can be composed by 1, 2 or 3 busbars per phase, according to the requested rated current, short-circuit withstand and environmental conditions in terms of temperature, altitude and humidity.
Busbars are normally bare copper made, but upon request they can be suitably treated: tinned, silver-plated and/or sheathed.
[ABB]Отсек шин
Отсек шин расположен в средней секции НКУ.
Сборные шины могут быть расположены в верхней, в центре или в нижней части НКУ в зависимости от выбранного конструктивного решения.
Они предназначены для распределения электроэнергии в различные функциональные блоки НКУ.
Во многих конструктивных решениях сборные шины подают электропитание непосредственно на автоматические выключатели.
Распределительные шины расположены вертикально и подают электропитание на автоматические выключатели отходящих линий.
Шины могут быть выполнены в виде пакетов, состоящих из одной, двух или трех полос, что определяется требуемым номинальным током, прочностью при коротких замыканиях и условиями окружающей среды при эксплуатации: температурой, влажностью и высотой расположения над уровнем моря.
В стандартном исполнении применяются медные неизолированные шины. По требованию НКУ может быть оснащено обработанными шинами: лужеными, посеребренными и/или изолированными.
[Перевод Интент]Тематики
- НКУ (шкафы, пульты,...)
Синонимы
EN
Русско-английский словарь нормативно-технической терминологии > отсек шин
См. также в других словарях:
depending on — adjective determined by conditions or circumstances that follow (Freq. 8) arms sales contingent on the approval of congress • Syn: ↑contingent, ↑contingent on, ↑contingent upon, ↑dependent on, ↑dependant on, ↑ … Useful english dictionary
Cutaneous conditions — There are many conditions of or affecting the human integumentary system the organ system that comprises the entire surface of the body and includes skin, hair, nails, and related muscle and glands.[1] Contents 1 Diseases 2 History … Wikipedia
Shark Island Challenge — The Shark Island Challenge (SIC), held near Cronulla, New South Wales, Australia, is the most celebratedFact|date=March 2007 World Tour event in bodyboarding since the elimination of the Teahupoo Challenge (Teahupoo) from the world bodyboarding… … Wikipedia
coastal landforms — ▪ geology Introduction any of the relief features present along any coast, the result of a combination of processes, sediments, and the geology of the coast itself. The coastal environment of the world is made up of a wide variety of… … Universalium
Non-line-of-sight propagation — Non line of sight (NLOS) or near line of sight is a term used to describe radio transmission across a path that is partially obstructed, usually by a physical object in the innermost Fresnel zone. Many types of radio transmissions depend, to… … Wikipedia
Spawn (biology) — The spawn (eggs) of a clownfish. The black spots are the eyes developing. Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm,… … Wikipedia
Fuse (explosives) — In an explosive, pyrotechnic device or military munition, a fuse (or fuze) is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately. However, when being specific (and in particular in a military… … Wikipedia
Underwater searches — are procedures carried out by divers in order to find a known or suspected target object or objects in a specified search area under water. There are a number of techniques in general use by Commercial, Scientific, Public service, Military, and… … Wikipedia
Asexual reproduction — in liverworts: a caducous phylloid germinating Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy… … Wikipedia
Uranium — (pronEng|jʊˈreɪniəm) is a silvery gray metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. It has 92 protons and 92 electrons, 6 of them valence electrons. It can have between 141 and … Wikipedia
Variable displacement — is an automobile engine technology that allows the engine displacement to change, usually by deactivating cylinders, for improved fuel economy. The technology is primarily used in large, multi cylinder engines. Many automobile manufacturers have… … Wikipedia