-
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
-
2 изоляция (процесс)
изоляция (процесс)
—
[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
insulation (process)
The process of preventing or reducing the transmission of electricity, heat, or sound to or from a body, device, or region by surrounding it with a nonconducting material. (Source: CED)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
DE
FR
Русско-французский словарь нормативно-технической терминологии > изоляция (процесс)
-
3 термоизоляция
термоизоляция
—
[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]EN
thermal insulation
The process of preventing the passage of heat to or from a body by surrounding it with a nonconducting material. (Source: CED)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]Тематики
EN
DE
FR
Русско-французский словарь нормативно-технической терминологии > термоизоляция
-
4 insulate
['insjuleit](to cover, protect or separate (something) with a material that does not let especially electrical currents or heat etc pass through it: Rubber and plastic are used for insulating electric wires and cables.) isoler -
5 снимаемый экран
снимаемый экран
экран по изоляции, выполненный из экструдированного материала, который может быть полностью снят без специального инструмента, растворителя, нагревания или комбинации этих средств [IEV number 461-03-05]EN
strippable screen
insulation screen made of an extruded material that can be fully removed without a special tool, a solvent, the application of heat or by any combination of these
[IEV number 461-03-05]FR
écran pelable
écran sur enveloppe isolante constitué d'un matériau extrudé qui peut être retiré complètement sans l'aide d'un outil spécial, d'un solvant, de l'action de la chaleur ou de toute combinaison de ces moyens
[IEV number 461-03-05]
Тематики
- кабели, провода...
EN
DE
- abziehbare äußere Leitschicht, f
FR
Русско-французский словарь нормативно-технической терминологии > снимаемый экран
См. также в других словарях:
Heat transfer — is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase change … Wikipedia
Insulation — Materials that prevent or slow down the movement of heat. *** Any material or substance that provides a high resistance to the flow of heat from one surface to another. The different types include blanket or batt, foam, or loose fill, which … Energy terms
Heat-shrink tubing — (or commonly heat shrink ) is a tube which shrinks in diameter when heated. Its diameter and thickness can vary, and there are three main categories, thin wall, medium wall and thick wall tube. Heat shrink is used to insulate wires, connections,… … Wikipedia
Insulation — may mean:* Building insulation, added to buildings for comfort and energy efficiency * Soundproofing, also known as acoustic insulation, any means of reducing the intensity of sound * Thermal insulation, materials used to reduce the rate of heat… … Wikipedia
Insulation — In su*la tion, n. 1. The act of insulating, or the state of being insulated; detachment from other objects; isolation. [1913 Webster] 2. (Elec. & Thermotics) The act of separating a body from others by nonconductors, so as to prevent the transfer … The Collaborative International Dictionary of English
insulation, thermal — Material which is a poor conductor of heat; used to retard or slow down flow of heat through wall or partition … Dictionary of automotive terms
insulation — Material used to prevent the passage or leakage of electricity, heat, or sound. A wrapping of nonconductive material around a wire intended to carry an electric current, for the purpose of preventing the discharge of electricity from the wire and … Ballentine's law dictionary
Heat capacity — Thermodynamics … Wikipedia
insulation — noun 1. the state of being isolated or detached (Freq. 1) the insulation of England was preserved by the English Channel • Syn: ↑insularity, ↑insularism, ↑detachment • Derivationally related forms: ↑insular ( … Useful english dictionary
Heat — In physics, heat, symbolized by Q , is energy transferred from one body or system to another due to a difference in temperature. [cite book|author= Daintith, John |title=Oxford Dictionary of Physics|publisher=Oxford University… … Wikipedia
insulation — 1. The act of insulating. 2. The nonconducting substance so used. 3. The state of being insulated. * * * in·su·la·tion .in(t) sə lā shən n 1) the action of separating a conductor from conducting bodies by means of nonconductors so as to prevent… … Medical dictionary
