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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 measure
measure ⇒ Length measurement, Surface area measurements, Capacity measurement, Volume measurement, Weight measurement, SizesA n1 ( unit) unité f de mesure ; weights and measures les poids mpl et mesures fpl ; a measure of length une unité de longueur ; liquid measure mesure f de capacité pour les liquides ; to make sth to measure faire qch sur mesure ; it's made to measure ( garment) c'est fait sur mesure, c'est du sur mesure ;2 (standard amount, container) mesure f ; a double measure of vodka une double mesure de vodka ; he gave me short measure, I got short measure il a triché sur la quantité ;3 ( device for measuring) instrument m de mesure ;4 fig (qualified amount, extent) some ou a certain measure of un/-e certain/-e ; a measure of respect/success/change un certain respect/succès/changement ; to receive only a small measure of support ne recevoir qu'un soutien limité ; a good ou wide measure of autonomy une grande autonomie ; in large measure dans une large mesure ; she despised them and envied them in equal measure elle les méprisait autant qu'elle les enviait ; to distribute praise and blame in equal measure faire autant de compliments que de critiques ; in full measure [feel, possess, fulfil, contribute] pleinement ; [repay] entièrement ; [suffer] profondément ;5 (way of estimating, indication) ( of price rises) mesure f ; (of success, anger, frustration etc) mesure f, indication f ; (of efficiency, performance) critère m ; to be the measure of donner la mesure de ; to give some measure of donner une idée de [delight, failure, talent, arrogance etc] ; to use sth as a measure of utiliser qch pour mesurer [effects, impact, success] ; this is a measure of how dangerous it is ceci montre à quel point c'est dangereux ; this is a measure of how seriously they are taking the situation ceci montre à quel point ils prennent la situation au sérieux ; that is a measure of how well the company is run cela mesure la qualité de la gestion de la société ;6 ( assessment) beyond measure [change, increase] énormément ; [anxious, beautiful, difficult] extrêmement ; it has improved beyond measure il y a eu d'énormes progrès ; to take the measure of sb jauger qn ; I have the measure of them je sais ce qu'ils valent ;7 (action, step) mesure f (against contre ; to do pour faire) ; to take measures prendre des mesures ; safety ou security measure mesure de sécurité ; measures aimed at doing des mesures destinées à faire ; to do sth as a precautionary/an economy measure faire qch par mesure de précaution/d'économie ; as a preventive measure à titre préventif ; as a temporary measure provisoirement ; the measure was defeated Pol Jur la mesure a été rejetée ;B vtr1 ( by standard system) [person, instrument] mesurer [length, rate, depth, person, waist] ; to measure sth in mesurer qch en [metres, inches] ; to get oneself measured for faire prendre ses mesures pour ; over a measured kilometre Sport sur un kilomètre (délimité par des balises) ; to measure sth into mesurer qch dans [container] ;2 ( have a measurement of) mesurer ; to measure four by five metres mesurer quatre mètres sur cinq ; a tremor measuring 5.2 on the Richter scale une secousse de 5,2 sur l'échelle de Richter ;3 ( assess) mesurer [performance, ability, success, popularity] ; they measure their progress by the number of ils mesurent leur progrès au nombre de ;C vi [person, instrument] mesurer.for good measure pour faire bonne mesure ; to do things by half-measures se contenter de demi-mesures ; there can be no half-measures il ne saurait être question de demi-mesures.■ measure off:▶ measure off [sth] mesurer [fabric, ribbon etc].■ measure out:▶ measure out [sth] mesurer [land, flour, liquid] ; doser [medicine] ; compter [drops].■ measure up:▶ measure up [person] avoir les qualités requises ; [product] être de qualité ; to measure up against sb être l'égal de qn ; to measure up to être à la hauteur de [expectations] ; soutenir la comparaison avec [achievement] ;▶ measure up [sth] mesurer [room etc]. -
3 scope
scope n1 ( opportunity) possibilité f ; scope for sth possibilité(s) de qch ; scope for sb to do possibilités pour qn de faire ; to have scope to do avoir la possibilité de faire ; to give sb scope to do laisser toute latitude à qn de faire ;2 (range, extent) ( of plan) envergure f ; (of inquiry, report, study) portée f ; (of changes, disaster, knowledge, power) étendue f ; ( of textbook) champ m, portée f ; the research is broad/narrow in scope le champ de la recherche est large/étroit ; to be within/outside the scope of the study faire partie du/sortir du champ de l'étude ; to fall within the scope of the survey rentrer dans le champ du sondage ; to extend the scope of the investigation élargir le champ de l'enquête ;3 ( capacity) compétences fpl ; to be within/beyond the scope of sb entrer dans/dépasser les compétences de qn ;4 Ling portée f.
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