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1 комплексное расслоение
Русско-английский физический словарь > комплексное расслоение
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2 комплексное расслоение
complex bundle мат., complex foliationРусско-английский научно-технический словарь Масловского > комплексное расслоение
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3 комплексное расслоение
Mathematics: complex bundle, complex foliationУниверсальный русско-английский словарь > комплексное расслоение
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4 Расслоение комплексно сопряженное
Русско-английский словарь по прикладной математике и механике > Расслоение комплексно сопряженное
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5 комплексно-сопряженное расслоение
complex conjugate bundle матем.Русско-английский научно-технический словарь Масловского > комплексно-сопряженное расслоение
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6 группа
1) General subject: act (группа исполнителей, например, рок/поп-банда) пример: Other Scottish acts, such as the Mull Historical Society who also featured in the top 50, performed at a party in Glasgow where the result was announced.), aggies (Aggies), assemblage, band (организованная; людей), (организованная) bander (людей), batch, bevy, block, body, bracket, brass choir (инструментов), bunch, circle (людей), class, cluster bar, cohorts, complex (зданий), drover, flock, gang, group, handful, hands, herd, knot (людей), lay-out, league, mob (людей), octuplicate, outfit, pack, packet, parcel, party, persuasion, plump, posse, prong, series, set, tally, team, type, automatic call distribution split (Метод маршрутизации вызовов схожего типа между агентами в операторском центре. А также группа, укомплектованная агентами, обученными обслуживать определенный тип входящих вызовов.), clutch, (лиц, людей, например) body of3) Biology: bunch (животных), cluster (деревьев)5) Medicine: residue, (воздействия) treatment arm (в контексте клинических исследований; целесообразно оставлять просто "группа"), (испытуемых, пациентов) arm (в контексте научных исследований по сравнению групп, получающих разное лечебное воздействие)7) Obsolete: nation (a nation of newspaper readers — люди, читающие газеты)8) Sports: bunch (велосипедистов)10) Engineering: array, bank (баллонов, трансформаторов и т. п.), crew, ensemble, manning, pear (конвертера), radical, train (прокатных клетей или валков)11) Agriculture: bunch (животных или птиц), loose grasses (животных или птиц)14) Construction: clump (деревьев)15) Mathematics: R-group R, assembly, cell, cluster, cohort, collection, gp (group), inquiry ensemble, item (данных), item of data (данных), pool, transvection-rich group16) British English: group (материнская компания вместе с дочерними предприятиями)17) Railway term: complication, row18) Law: delinquent gang, element (людей), violent gang19) Economy: committee, kin group, kinship group20) Accounting: batch (требований), bracket (напр. при группировке налогоплательщиков по доходу), group (компаний), group of companies (компаний), inspection team (технического контроля), stratum21) Automobile industry: panel22) Artillery: straddle23) Diplomatic term: side24) Forestry: bunch (при посеве или посадке гнёздами или биогруппами), clump (стволов или побегов с общей корневой системой), nest (напр. при посеве или посадке гнёздами или биогруппами)25) Metallurgy: line26) Polygraphy: division27) Politics: club (особ. держав)29) Electronics: bundle30) Jargon: crowd31) Information technology: constellation (одинаковых элементов, образующих макроэлемент), group box (Ряд интерфейсных элементов, объединённых вместе для удобства работы с ними), group item (как элемент данных), heading, section32) Oil: mix (сейсмоприёмников, пунктов взрыва), mix (сейсмоприемников; пунктов взрыва), patch array, pattern array34) Simple: caboodle35) Geophysics: pattern37) Seismology: template40) Network technologies: Computer Emergency Response Team, frame43) Quality control: batch (напр- требований, поступающих в систему массового обслуживания), battery (одинаковых деталей или установок), (рабочая) committee44) Robots: function( функциональная) (напр. разработчиков)45) Arms production: group (артиллерии), team (боевая или тактическая)47) Makarov: aggregation, batch (частиц, волн), bath, bunch (частиц, волн), clump (предметов), cluster (однородных предметов и т.п.), cluster (частиц, волн), constellation (напр., одинаковых элементов), crew (сотрудников), drove, framework, group (сотрудников), order, pack (однородных объектов), package (однородных объектов), pattern (сейсмическая), pile (однородных объектов), quality, row (однотипных объектов), team (сотрудников), train (волн)49) Gold mining: field crew50) SAP.tech. corporate group, grp -
7 комплексно-сопряжённое расслоение
Mathematics: complex conjugate bundle (данному)Универсальный русско-английский словарь > комплексно-сопряжённое расслоение
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8 комплект
1) General subject: array (чего-л.), bevy, complement, file, gang, package, set, set out, shook (досок на один ящик), suite, series, suit2) Medicine: assembly3) Colloquial: set-out4) Obsolete: equipage (украшений, посуды)5) Military: ensemble, load, load (материальных средств), mission equipment package, mix, (технический) suite (оборудования)6) Engineering: assemblage, battery, deck (магнитных лент), group, kit part, nest, outfit, shook (деталей на один ящик, клёпки на одну бочку), stack9) Construction: gang (инструментов, машин, механизмов)10) Mathematics: complete series, complex11) Railway term: complete unit, matched set15) Music: set (полный комплект струн)16) Polygraphy: file (газет), operation registry, operation registry (напр. микрофильмов), stand17) Electronics: deck18) Jargon: package deal19) Information technology: bundle20) Oil: gang (инструментов)21) Special term: bank22) Perfume: collection23) Advertising: range24) Patents: lay-out25) Business: basket, completion, layout, unit26) Industrial economy: complete set27) Programming: a set of several28) Automation: pack29) General subject: set (если речь идет об отдельном наборе)30) Chemical weapons: kit (инструментов)31) Makarov: bevy (каких-л. предметов), clump, file (документов), kit (измерит. приборов, инструментов), kit (напр. инструментов, оборудования), kit (напр. реактивов), outfit (приборов, инструментов, принадлежностей), range (мебели), repertory, set (см тж. kit), stack (пластин)32) Archaic: equipage (украшений, посуды и т.п.)34) Electrical engineering: kit (напр. инструментов)35) Microsoft: kit item -
9 множество признаков
Linguistics: feature bundle, feature complex, feature setУниверсальный русско-английский словарь > множество признаков
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10 объединение
1) General subject: aggregating, alliance, amalgamation, association, banding (действие), co-operation, coalescence (в группы), coalition, combine, community, copulation, corporation, embodiment, federation, fusion, hui, incorporation, merger, pool, rally, reunion (бывших противников), society, team up, team-up, unification, union, unionization, unifying, cluster, gathering2) Medicine: aggregation3) French: bloc4) Obsolete: conjuncture5) Literal: solder6) Military: build-up, command, force, large command, large unit, (воинская) military formation7) Engineering: collating (перфокарт), collation (перфокарт), conjunction, consolidation (предприятий), crowding, firm, integration, merge, merging, multiplex, multiplexing8) Bookish: consociation9) Construction: venture10) Mathematics: aggregate, collection, grouping, integrating, join, population, sum (множеств), syndicate, the sum total, totality, universe11) Religion: consociation (An association in fellowship or alliance)12) British English: company13) Railway term: commoning, interconnection (энергосистем)14) Law: block, connection (политическое, коммерческое), connexion (политическое, коммерческое), joinder, joining, junction, rejoinder, uniting (of states) (государств)15) Economy: link-up (фирм), pool (картельного типа между конкурентами), pool (соглашение картельного типа между конкурентами), pooling (напр. прибылей), unification of products16) Accounting: amalgamation (различаются два типа - поглощение и слияние), combination (различаются два типа - поглощение и слияние), institution, linking17) Architecture: unification (действие)18) Diplomatic term: union (государств)19) Information technology: collate, crowd, mesh, meshing, pack (нескольких элементов данных в памяти), packing (нескольких элементов данных в памяти), trunking (каналов), union (в ООП), uniting20) Astronautics: combining, splicing, incorporating21) Geophysics: (сейсмических профилей) merging23) Patents: incorporation (признаков изобретения)24) Business: fusing, organization, consortium25) SAP. bundle26) Drilling: interconnection (напр. систем)27) Sakhalin energy glossary: field office28) American English: association or merger ( civilian), formation (military)30) leg.N.P. corporation (as distinguished from "foundation")31) General subject: merge (потоков масла гидросистемы)32) Makarov: amalgam, amalgamate, assemblage, assembling, assembly, band, banking, block (блок), body corporate, building (of compound members), community (людей), complex, front, fuse, ganging (в группу), integration (в одно целое), merger (банков, предприятий и т.п.), packaging, packing (команд), rally (сил, действий), synthesis33) Ethology: affiliation34) SAP.fin. bolt-on35) Logistics: consolidating36) Foreign Ministry: major formation37) Electrical engineering: interconnection (энергосистемы) -
11 пучок признаков
Linguistics: feature bundle, feature complex, feature set -
12 Г-135
не успел (И) ГЛАЗОМ МОРГНУТЬ (МИГНУТЬ) coll these forms only infin compl of не успел, often used in neg pfv fut, gener. 2nd pers sing не успеешь usu. the 1st clause in a complex sent, foil. by a clause introduced by Conj «как» or «a») (some person did not have time) to realize sth. or react to sth. (because it happened so quickly)X не успел глазом моргнуть - before X could bat an eye (an eyelid, an eyelash)before X had time to blink before X knew it. Cf. before X can (could) say Jack Robinson.«Не мой (ребёнок)», - сказал Алтынник и облизнул губы. «Ах, не твой? - вскрикнула Людмила. - Вот тебе!» И Алтынник не успел глазом моргнуть, как сверток очутился в пыли у его ног (Войнович 5). "It's not mine (my child)," said Altinnik, licking his lips. uAch, it's not yours?" screeched Ludmilla. "Here, you take him'" Before Altinnik could bat an eye, the bundle was in the dust at his feet (5a). -
13 глазом мигнуть
• НЕ УСПЕЛ (И) ГЛАЗОМ МОРГНУТЬ < МИГНУТЬ> coll[these forms only; infin compl of не успел, often used in neg pfv fut, gener. 2nd pers sing не успеешь; usu. the 1st clause in a complex sent, foll. by a clause introduced by Conj " как" or " а"]=====⇒ (some person did not have time) to realize sth. or react to sth. (because it happened so quickly):- X не успел глазом моргнуть≈ before X could bat an eye <an eyelid, an eyelash>;- before X knew it. Cf. before X can < could> say Jack Robinson.♦ "Не мой [ребенок]", - сказал Алтынник и облизнул губы. "Ах, не твой? - вскрикнула Людмила. - Вот тебе!" И Алтынник не успел глазом моргнуть, как сверток очутился в пыли у его ног (Войнович 5). "It's not mine [my child]," said Altinnik, licking his lips. "Ach, it's not yours?" screeched Ludmilla. "Here, you take him'" Before Altinnik could bat an eye, the bundle was in the dust at his feet (5a).Большой русско-английский фразеологический словарь > глазом мигнуть
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14 глазом моргнуть
• НЕ УСПЕЛ (И) ГЛАЗОМ МОРГНУТЬ < МИГНУТЬ> coll[these forms only; infin compl of не успел, often used in neg pfv fut, gener. 2nd pers sing не успеешь; usu. the 1st clause in a complex sent, foll. by a clause introduced by Conj " как" or " а"]=====⇒ (some person did not have time) to realize sth. or react to sth. (because it happened so quickly):- X не успел глазом моргнуть≈ before X could bat an eye <an eyelid, an eyelash>;- before X knew it. Cf. before X can < could> say Jack Robinson.♦ "Не мой [ребенок]", - сказал Алтынник и облизнул губы. "Ах, не твой? - вскрикнула Людмила. - Вот тебе!" И Алтынник не успел глазом моргнуть, как сверток очутился в пыли у его ног (Войнович 5). "It's not mine [my child]," said Altinnik, licking his lips. "Ach, it's not yours?" screeched Ludmilla. "Here, you take him'" Before Altinnik could bat an eye, the bundle was in the dust at his feet (5a).Большой русско-английский фразеологический словарь > глазом моргнуть
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15 и глазом мигнуть
• НЕ УСПЕЛ (И) ГЛАЗОМ МОРГНУТЬ < МИГНУТЬ> coll[these forms only; infin compl of не успел, often used in neg pfv fut, gener. 2nd pers sing не успеешь; usu. the 1st clause in a complex sent, foll. by a clause introduced by Conj " как" or " а"]=====⇒ (some person did not have time) to realize sth. or react to sth. (because it happened so quickly):- X не успел глазом моргнуть≈ before X could bat an eye <an eyelid, an eyelash>;- before X knew it. Cf. before X can < could> say Jack Robinson.♦ "Не мой [ребенок]", - сказал Алтынник и облизнул губы. "Ах, не твой? - вскрикнула Людмила. - Вот тебе!" И Алтынник не успел глазом моргнуть, как сверток очутился в пыли у его ног (Войнович 5). "It's not mine [my child]," said Altinnik, licking his lips. "Ach, it's not yours?" screeched Ludmilla. "Here, you take him'" Before Altinnik could bat an eye, the bundle was in the dust at his feet (5a).Большой русско-английский фразеологический словарь > и глазом мигнуть
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16 и глазом моргнуть
• НЕ УСПЕЛ (И) ГЛАЗОМ МОРГНУТЬ < МИГНУТЬ> coll[these forms only; infin compl of не успел, often used in neg pfv fut, gener. 2nd pers sing не успеешь; usu. the 1st clause in a complex sent, foll. by a clause introduced by Conj " как" or " а"]=====⇒ (some person did not have time) to realize sth. or react to sth. (because it happened so quickly):- X не успел глазом моргнуть≈ before X could bat an eye <an eyelid, an eyelash>;- before X knew it. Cf. before X can < could> say Jack Robinson.♦ "Не мой [ребенок]", - сказал Алтынник и облизнул губы. "Ах, не твой? - вскрикнула Людмила. - Вот тебе!" И Алтынник не успел глазом моргнуть, как сверток очутился в пыли у его ног (Войнович 5). "It's not mine [my child]," said Altinnik, licking his lips. "Ach, it's not yours?" screeched Ludmilla. "Here, you take him'" Before Altinnik could bat an eye, the bundle was in the dust at his feet (5a).Большой русско-английский фразеологический словарь > и глазом моргнуть
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17 узел I
............................................................1. knot(vt. & n.) گره، برکمدگی، دژپیه، غده، چیز سفت یا غلنبه، مشکل، عقده، واحد سرعت دریایی معادل 6076.10 فوت در ساعت، گره زدن، بهم پیوستن، گیر انداختن، گره خوردن، منگوله دار کردن، گره دریایی............................................................2. tangle(vt. & n.) درهم و برهم کردن، درهم پیچیدن، گرفتار کردن، گیر افتادن، درهم گیر انداختن، گوریده کردن............................................................3. junction(n.) پیوندگاه، انشعاب، نقطه اتصال، اتصال، برخوردگاه............................................................4. centre(vt. & vi. & n.) میان، مرکز، وسط و نقطه مرکزی، درمرکز قرار گرفتن، تمرکز یافتن............................................................5. complex(n.) مجتمع، گروهه، مجموعه، عقده (oghdeh)، آچار، هم تافت(adj.) پیچیده، مرکب از چند جزء، بغرنج، مختلط............................................................6. protuberance(protuberancy=)(n.) برآمدگی، قلنبگی، تورم، باد کردگی............................................................7. assembly(n.) همگذاری، مجمع، اجتماع، انجمن، مجلس، گروه، هیئت قانون گذاری............................................................8. unit(n.) واحد، میزان، یگان، شمار، یک دستگاه، فرد، نفر، عدد فردی، یکه............................................................9. pack(vt. & n.) بسته، بقچه، بسته کردن، کوله پشتی، دسته، گروه، یک بسته (مثل بسته سیگاروغیره)، یکدست ورق بازی، بسته بندی کردن، قرار دادن، توده کردن، به زور چپاندن، بار کردن، بردن، فرستادن............................................................10. bundle(vt. & n.) بقچه، بسته، مجموعه، دسته کردن، به صورت گره درآوردن، بقچه بستن -
18 длительный допустимый ток
- Strombelastbarkeit, f
- Dauerstrombelastbarkeit, f
(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-немецкий словарь нормативно-технической терминологии > длительный допустимый ток
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19 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
-
20 длительный допустимый ток
- courant permanent admissible, m
- courant admissible, m
(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-французский словарь нормативно-технической терминологии > длительный допустимый ток
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