temperature+value

(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 I_Z
[ 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

• длительно допустимый ток
• допустимый ток

EN

• ampacity (US)
• continuous current
• continuous current-carrying capacity
• current-carrying capacity

DE

• Dauerstrombelastbarkeit, f
• Strombelastbarkeit, f

FR

• courant admissible, m
• courant permanent admissible, m

температура океана
—
[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]

EN

ocean temperature
A measure, referenced to a standard value, of the heat or coldness in a body of oceanic water. (Source: RHW)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]

Тематики

• охрана окружающей среды

EN

• ocean temperature

DE

• Meerestemperatur

FR

• température de l'océan

использование теплотворной способности
—
[ http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]

EN

utilisation of calorific value
Calorific value is the heat per unit mass produced by complete combustion of a given substance. Calorific values are used to express the energy values of fuels; usually these are expressed in megajoules per kilogram. They are also used to measure the energy content of foodstuffs; i.e. the energy produced when the food is oxidized in the body. The units here are kilojoules per gram. Calorific values are measured using a bomb calorimeter (apparatus consisting of a strong container in which the sample is sealed with excess oxygen and ignited electrically. The heat of combustion at constant volume can be calculated from the resulting rise in temperature). (Source: DICCHE)
[http://www.eionet.europa.eu/gemet/alphabetic?langcode=en]

Тематики

• охрана окружающей среды

EN

• utilisation of calorific value

DE

• Brennwertnutzung

FR

• utlisation du pouvoir calorifique

коэффициент циклической токовой нагрузки (кабелей)
Коэффициент, на который может быть умножен номинальный ток установившегося режима, соответствующий коэффициенту нагрузки 100 %, для получения допустимого пикового значения тока в течение суточного цикла, при котором температура токопроводящей жилы в течение этого цикла достигает, но не превышает максимально допустимое значение
[IEV number 461-23-02]

EN

cyclic rating factor
factor by which the permissible steady-state rated current corresponding to a 100 % load factor may be multiplied to obtain the permissible peak value of current during a daily cycle such that the conductor attains, but does not exceed, the maximum rated temperature during the cycle
[IEV number 461-23-02]

FR

facteur de régime cyclique
facteur par lequel le courant assigné admissible en régime permanent, correspondant à un facteur de charge 100 %, peut être multiplié pour obtenir la valeur de pointe du courant au cours d'un cycle journalier, de sorte qu'au cours de ce cycle, l'âme atteigne sans la dépasser la température assignée maximale
[IEV number 461-23-02]

Тематики

• кабели, провода...

EN

• cyclic rating factor

DE

• Bemessungsfaktor für zyklische Last

FR

• facteur de régime cyclique

полное сопротивление короткого замыкания пары обмоток
Сопротивление, равное Z = R + jХ, Ом, определяемое при номинальной частоте и расчетной температуре между выводами одной из обмоток пары, при замкнутой накоротко другой обмотке этой пары и разомкнутых остальных обмотках при их наличии. Для трехфазного трансформатора полное сопротивление короткого замыкания пары обмоток является полным сопротивлением фазы (в эквивалентной схеме соединения «звезда»).
В трансформаторе, имеющем обмотку с ответвлениями, полное сопротивление короткого замыкания относят к конкретному ответвлению. Если в НД не оговорено иное, выбирают основное ответвление.
Примечание — Полное сопротивление короткого замыкания пары обмоток может быть выражено в относительных значениях z, например в процентах базисного полного сопротивления короткого замыкания Zбаз той же обмотки пары
Z=100Z/Zбаз
Где Zбаз=U²/Sном
(для трехфазных и однофазных трансформаторов), Ом (U — напряжение (номинальное или напряжение ответвления) обмотки, к которой относятся Z и Zбаз, В; Sном — номинальная мощность основного ответвления трансформатора, В•А).
Относительное значение полного сопротивления короткого замыкания может быть также определено как отношение напряжения, приложенного к данной обмотке в опыте короткого замыкания, вызывающего протекание через эту обмотку номинального тока (либо тока ответвления), к номинальному напряжению этой обмотки (либо напряжению ответвления). Это приложенное напряжение определяют как напряжение короткого замыкания (МЭС 421-07-01) данной пары обмоток и, как правило, выражают в процентах
(МЭС 421-07-02).
[ ГОСТ 30830-2002]

EN

short-circuit impedance of a pair of windings
the equivalent star connection impedance related to one of the windings, for a given tapping and expressed in ohms per phase, at rated frequency, measured between the terminals of a winding when the other winding is short-circuited
NOTE – This value is normally related to the appropriate reference temperature
[IEV number 421-07-02]

FR

impédance de court-circuit d'une paire d'enroulements
impédance équivalente en connexion étoile, rapportée à l'un des enroulements, pour une prise donnée et exprimée en ohms par phase, à la fréquence assignée, mesurée aux bornes d'un enroulement lorsque l'autre enroulement est en court-circuit
NOTE – Cette valeur est normalement rapportée à une température de référence appropriée.
[IEV number 421-07-02]

Тематики

• трансформатор

Классификация

EN

• short-circuit impedance of a pair of windings

DE

• Kurzschlußimpedanz eines Wicklungspaares

FR

• impédance de court-circuit d'une paire d'enroulements

облучение продуктов питания
—
[ 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

• охрана окружающей среды

EN

• food irradiation

DE

• Lebensmittelbestrahlung

FR

• irradiation des aliments