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1 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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2 энергия ГЭС
энергия ГЭС
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
hydroelectric energy
The free renewable source of energy provided by falling water that drives the turbines. Hydropower is the most important of the regenerable energy sources because of its highest efficiency at the energy conversion. There are two types of hydroelectric power plants: a) run-of-river power plants for the use of affluent water; b) storage power plants (power stations with reservoir) where the influx can be regulated with the help of a reservoir. Mostly greater differences in altitudes are being used, like mountain creeks. Power stations with reservoirs are generally marked by barrages with earth fill dam or concrete dams. Though hydropower generally can be called environmentally acceptable, there exist also some problems: a) change of groundwater level and fill up of the river bed with rubble. b) Risk of dam breaks. c) Great demand for land space for the reservoir. d) Diminution, but partly also increase of value of recreation areas. As the hydropowers of the world are limited, the world energy demand however is rising, finally the share of hydropower will decrease. (Source: PORT / PHC / PZ)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
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FR
Русско-немецкий словарь нормативно-технической терминологии > энергия ГЭС
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3 воздействие производства энергии на окружающую среду
воздействие производства энергии на окружающую среду
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
environmental impact of energy
Energy and environmental problems are closely related, since it is nearly impossible to produce, transport, or consume energy without significant environmental impact. The environmental problems directly related to energy production and consumption include air pollution, water pollution, thermal pollution, and solid waste disposal. The emission of air pollutants from fossil fuel combustion is the major cause of urban air pollution. Diverse water pollution problems are associated with energy usage. One major problem is oil spills. In all petroleum-handling operations, there is a finite probability of spilling oil either on the earth or in a body of water. Coal mining can also pollute water. Changes in groundwater flow produced by mining operations often bring otherwise unpolluted waters into contact with certain mineral materials which are leached from the soil and produce an acid mine drainage. Solid waste is also a by-product of some forms of energy usage. Coal mining requires the removal of large quantities of earth as well as coal. In general, environmental problems increase with energy use and this combined with the limited energy resource base is the crux of the energy crisis. An energy impact assessment should compare these costs with the benefits to be derived from energy use. (Source: RAU)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
DE
FR
Русско-немецкий словарь нормативно-технической терминологии > воздействие производства энергии на окружающую среду
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4 внутригородской район
внутригородской район
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
inner city
1) Part of a city at or near the centre, especially a slum area where poor people live in bad housing.
2) City centres of many industrialized countries which exhibit environmental degradation. The numerous and highly competitive activities entailing land use overwhelm the limited space and create a situation of overcrowding, functional incompatibility and cultural degradation. Inner city areas have a high level of commercial specialization, a large number of offices and a sizeable daytime population. At the same time, city centres generally remain a sort of ghetto for a permanent, low-income population living in run-down housing and enjoying little in the way of public services and civic amenities. The concentration of service industries inevitably entails the replacement of traditional housing and shops by office blocks, the provision of basic utilities at the expense of civic amenities and the provision of major access roads which eat up urban space. Structures of historic origin are often unable to meet modern requirements and, notwithstanding their value, frequently face demolition.
(Source: PHC / WPR)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
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FR
Русско-немецкий словарь нормативно-технической терминологии > внутригородской район
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5 ДДТ
ДДТ
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[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
DDT
A persistent organochlorine insecticide, also known as dichlorodiphenyltrichloroethane, that was introduced in the 1940s and used widely because of its persistence (meaning repeated applications were unnecessary), its low toxicity to mammals and its simplicity and cheapness of manufacture. It became dispersed all over the world and, with other organochlorines, had a disruptive effect on species high in food chains, especially on the breeding success of certain predatory birds. DDT is very stable, relatively insoluble in water, but highly soluble in fats. Health effects on humans are not clear, but it is less toxic than related compounds. It is poisonous to other vertebrates, especially fish, and is stored in the fatty tissue of animals as sublethal amounts of the less toxic DDE. Because of its effects on wildlife its use in most countries is now forbidden or strictly limited. (Source: MGH / ALL)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
DE
FR
Русско-немецкий словарь нормативно-технической терминологии > ДДТ
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