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1 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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2 цена земли
цена земли
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
land value
The monetary or material worth in commerce or trade of an area of ground considered as property. (Source: RHW)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
DE
FR
Русско-французский словарь нормативно-технической терминологии > цена земли
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3 цена на сельхозпродукцию
цена на сельхозпродукцию
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
agronomic value
The monetary or material worth at which buyers and sellers agree to do business for agricultural goods and services. (Source: AGP / RHW)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
DE
FR
Русско-французский словарь нормативно-технической терминологии > цена на сельхозпродукцию
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4 индекс устойчивости к трекингу
индекс устойчивости к трекингу
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[IEV number 442-01-42]EN
proof tracking index
PTI (abbreviation)
the numerical value of the proof voltage expressed in volts which a material can withstand without tracking under specified test conditions
Source: 212-01-45
[IEV number 442-01-42]FR
indice de tenue au cheminement
ITC (abréviation)
valeur numérique de la tension d'épreuve exprimée en volts, qu'un matériau peut supporter sans cheminement dans des conditions d'essai spécifiées
Source: 212-01-45
[IEV number 442-01-42]EN
DE
FR
Русско-французский словарь нормативно-технической терминологии > индекс устойчивости к трекингу
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5 месторождение полезных ископаемых
месторождение полезных ископаемых
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
mineral deposit
A mass of naturally occurring mineral material, e.g. metal ores or nonmetallic mineral, usually of economic value, without regard to mode of origin. (Source: BJGEO)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
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Русско-французский словарь нормативно-технической терминологии > месторождение полезных ископаемых
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6 облучение продуктов питания
облучение продуктов питания
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
food irradiation
The most recent addition to food preservation technologies is the use of ionizing radiation, which has some distinct advantages over conventional methods. With irradiation, foods can be treated after packaging, thus eliminating post-processing contamination. In addition, foods are preserved in a fresh state and can be kept longer without noticeable loss of quality. Food irradiation leaves no residues, and changes in nutritional value due to irradiation are comparable with those produced by other processes. Irradiation is the process of applying high energy to a material, such as food, to sterilize or extend its shelf-life by killing microorganisms, insects and other pests residing on it. Sources of ionizing radiation that have been used include gamma rays, electron beams and X-rays. Gamma rays are produced by radioactive isotopes such as Cobalt-60. Electron beams are produced by linear accelerators, which themselves are powered by electricity. The dose applied to a product is the most important factor of the process. At high doses, food is essentially sterilized, just as occurs in canning. Products so treated can be stored at room temperature almost indefinitely. Controversial and banned in some countries. (Source: IFSE / VCN)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
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FR
Русско-французский словарь нормативно-технической терминологии > облучение продуктов питания
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