-
1 frequency-to-current converter
Electrical engineering: FCCУниверсальный русско-английский словарь > frequency-to-current converter
-
2 LF welding current
Англо-русский словарь промышленной и научной лексики > LF welding current
-
3 Constant-Frequency Alternating Current
Abbreviation: CFACУниверсальный русско-английский словарь > Constant-Frequency Alternating Current
-
4 high frequency current
Универсальный русско-английский словарь > high frequency current
-
5 high-frequency current
Универсальный русско-английский словарь > high-frequency current
-
6 low-frequency current
Polymers: LFCУниверсальный русско-английский словарь > low-frequency current
-
7 line frequency current
ток строчной частоты (ток, используемый при строчном сканировании экрана электронным пучком)Англо-русский словарь промышленной и научной лексики > line frequency current
-
8 частота тока
-
9 длительный допустимый ток
(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-английский словарь нормативно-технической терминологии > длительный допустимый ток
-
10 частота тока
Русско-английский военно-политический словарь > частота тока
-
11 частота вызывного тока
Русско-английский словарь по информационным технологиям > частота вызывного тока
-
12 частота тока возбуждения вихретокового преобразователя
частота тока возбуждения вихретокового преобразователя
Ндп. рабочая частота
-
[ ГОСТ 24289-80]
частота тока возбуждения вихретокового преобразователя
Частота тока обмотки возбуждения
[Система неразрушающего контроля. Виды (методы) и технология неразрушающего контроля. Термины и определения (справочное пособие). Москва 2003 г.]Недопустимые, нерекомендуемые
Тематики
EN
16. Частота тока возбуждения вихретокового преобразователя
Ндп. Рабочая частота
Exciting current frequency of eddy current probe
-
Источник: ГОСТ 24289-80: Контроль неразрушающий вихретоковый. Термины и определения оригинал документа
Русско-английский словарь нормативно-технической терминологии > частота тока возбуждения вихретокового преобразователя
-
13 ток промышленной частоты
Русско-английский научный словарь > ток промышленной частоты
-
14 ток контрольной частоты
Русско-английский словарь по информационным технологиям > ток контрольной частоты
-
15 ток несущей частоты
Русско-английский словарь по информационным технологиям > ток несущей частоты
-
16 частота несущего тока
ток холостого хода — no-load current; open-circuit current
Русско-английский словарь по информационным технологиям > частота несущего тока
-
17 усилитель несущей частоты
Русско-английский научный словарь > усилитель несущей частоты
-
18 частота кодового сигнала
Русско-английский словарь по информационным технологиям > частота кодового сигнала
-
19 частота кодового сигнала
Telecommunications: code current frequencyУниверсальный русско-английский словарь > частота кодового сигнала
-
20 частота несущего тока
Telecommunications: carrier current frequencyУниверсальный русско-английский словарь > частота несущего тока
См. также в других словарях:
Frequency comb — A frequency comb is the graphic representation of the spectrum of a mode locked laser. An octave spanning comb can be used for mapping radio frequencies into the optical frequency range or it can be used to steer a piezoelectric mirror within a… … Wikipedia
Current density imaging — (CDI) is an extension of magnetic resonance imaging (MRI), developed at the University of Toronto. It employs two techniques for spatially mapping electrical current pathways through tissue: LF CDI, low frequency CDI, the original implementation… … Wikipedia
Frequency-hopping spread spectrum — (FHSS) is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. A spread spectrum transmission offers three main advantages over… … Wikipedia
Frequency (producer) — Frequency Background information Birth name Bryan Fryzel Born January 4, 1983 … Wikipedia
Frequency (disambiguation) — Frequency refers to how often an event occurs within a period of time.It may also refer to: General * Audio frequency, a periodic vibration whose frequency is audible to the average human. * Statistical frequency, the number of times an event… … Wikipedia
Current Archaeology — Editor in Chief Andrew Selkirk Frequency Monthly Publisher Current Publishing First issue 1967 … Wikipedia
Frequency Specific Microcurrent — is a therapy based on neutralizing and eliminating disease radiations through the use of electronic equipment. The effect is achieved through neutralizing those frequencies that are alleged to be incorrect for the damaged or affected… … Wikipedia
Current Issues in Education — is an open access peer reviewed online academic journal sponsored by Arizona State University s Mary Lou Fulton Teachers College. The journal is run by ASU graduate students and publishes articles on a broad range of education topics that are… … Wikipedia
Current Cancer Drug Targets — Abbreviated title (ISO) Curr. Cancer Drug Targets Discipline … Wikipedia
Current Anthropology — Abbreviated title (ISO) CA, Curr Anthropol … Wikipedia
Current Science — Abbreviated title (ISO) Curr. Sci. Discipline Multidisciplinary … Wikipedia