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steady-state+value

  • 21 установившееся значение

    stationary value, steady-state value

    Русско-английский физический словарь > установившееся значение

  • 22 соответствовать установившейся практике

    Соответствовать установившейся практике-- The basic composition of the bath corresponds to usual practice. Соответствующий - appropriate (to); associated, involved, applicable, relevant, along the lines of (имеющий отношение к делу); proper, suitable, matching (подходящий); commensurate with, associated, corresponding (связанный зависимостью); corresponding, respective (при сопоставлении нескольких результатов, деталей); conforming to, complying with (подчиняющийся)
     The appropriate values are shown in Table and Fig.
     Physical properties appropriate to methanol boiling at atmospheric pressure were used throughout this analysis.
     It is important to note that the engine contained the normal regenerator disk and associated seals.
     It is possible that it [resonance] is not recognized as the casual agent and a general beefing-up of the parts involved is undertaken as a fix for the problem.
     The supplier shall establish procedures for identifying the product from applicable drawings.
     sT, sr are the stresses to give a specific strain or rupture in the lifetime of the vessel at the relevant temperature.
     Emergency shower, drench hose, and combination units are not a substitute for proper primary protective devices.
     A manipulator along the lines of Fig. has been examined by X.
     It is preferable to accept weaker weld metals with good ductility, rather than a weld metal which has matching strength but poor ductility.
     The atomizing air is preheated to the same temperature as the heated (temperature commensurate with 100 SSU viscosity) residual fuel oil entering the burner oil tube.
     Over the past few decades the generator capacity has been increasing steadily, warranting a corresponding increase in the rotor diameter.
     The initially measured value of the drag coefficient in each run is 10 percent to 12 percent higher than the corresponding steady-state value.
     Surrounding the stagnation zone are streak lines indicating that the fluid adjacent to the plate surface is flowing outward toward the respective edges.

    Русско-английский научно-технический словарь переводчика > соответствовать установившейся практике

  • 23 установившееся значение

    final value, steady-state value

    Русско-английский исловарь по машиностроению и автоматизации производства > установившееся значение

  • 24 установившееся значение

    conservative value, steady-state value

    Русско-английский политехнический словарь > установившееся значение

  • 25 стабильная величина

    Automation: steady-state value

    Универсальный русско-английский словарь > стабильная величина

  • 26 установившаяся величина

    Engineering: steady-state value

    Универсальный русско-английский словарь > установившаяся величина

  • 27 описываться

    Описываться - to be described, to be outlined, to be reported, to be represented, to be delineated (излагаться); to be governed, to obey (уравнением)
     The extensions to more complex loadings are described by P. [...].
     The basic analytical design approach used to establish specific cooling geometry arrangements for actual combustor application is outlined in [...].
     A case similar to the first series but with somewhat different conditions at the duct entry has also been reported in reference [...].
     The moving interface is represented by a succession of concentric circles.
     The steady state value of h for each heating rate is delineated by a horizontal line.
     However, wave propagation is nonuniform in the direction normal to the plane of the shear layer and is governed by (...).

    Русско-английский научно-технический словарь переводчика > описываться

  • 28 после чего

    После чего - after which, following which; whereupon, whereafter; at which point
     Annealed tensile bars to be rolled were obtained to predetermined levels after which they were sectioned.
     The test bar was then run up to the full speed of 12,500 rpm, whereupon the full test load was applied.
     Fuel is increased to a preestablished flow rate at which point the primary flow is gradually shut off.
     Starting with high values at early times, the heat transfer coefficient decreases sharply and attains a minimum, whereafter it increases and ultimately reaches a steady-state value.

    Русско-английский научно-технический словарь переводчика > после чего

  • 29 оценка состояния

    тупиковое состояние; тупик — dead state

    Русско-английский большой базовый словарь > оценка состояния

  • 30 значение

    * * *
    значе́ние с.
    1. ( размер величины) value, magnitude
    вычисля́ть значе́ние — compute [calculate] a value
    задава́ть значе́ние — pre-assign [preset, prescribe, predetermine, specify] a value
    нормирова́ть значе́ние — normalize a value
    ожида́ть значе́ние — expect a value
    определя́ть [оце́нивать] значе́ние — estimate a value
    принима́ть значе́ние
    1. (в расчётах, проектах) adopt [specify] a value
    2. (о какой-л. величине) take (on) [assume] a value
    уточня́ть значе́ние — ( определять окончательное значение) finalize a value; ( проверять) verify a value
    2. ( важность) significance
    3. (смысл, содержание) meaning, sense
    абсолю́тное значе́ние — absolute value, magnitude
    амплиту́дное значе́ние — peak [crest] value
    асимптоти́ческое значе́ние — asymptotic value
    бифуркацио́нное значе́ние — bifurcational value
    виртуа́льное значе́ние — virtual value
    гла́вное значе́ние — principal value
    грани́чное значе́ние — boundary value
    двоя́кое значе́ние — bifurcational value
    действи́тельное значе́ние — actual [real] value
    де́йствующее значе́ние — effective [root-mean-square, rms] value
    допусти́мое значе́ние — legitimate [admissible, allowed, allowable] value
    еди́нственное значе́ние — unique value
    запрещё́нное значе́ние — forbidden [unpermitted] value
    и́стинное значе́ние — стат., мат. ideal value; ( в логике) truth value
    значе́ние и́стинности — truth value
    коне́чное значе́ние — finite value
    максима́льное значе́ние
    1. maximum value
    2. эл. peak value
    мгнове́нное значе́ние — instantaneous value
    нача́льное значе́ние — initial value
    ненулево́е значе́ние — non-zero value
    нулево́е значе́ние — zero value
    оконча́тельное значе́ние — final value
    предвари́тельное значе́ние — tentative value
    преде́льное значе́ние — limiting value
    произво́льное значе́ние — arbitrary value
    равнове́сное значе́ние — equilibrium value
    разрешё́нное значе́ние — allowed [permitted] value
    разря́дное значе́ние — place value
    со́бственное значе́ние — characteristic [proper] value, eigenvalue; ( матрицы) latent root
    средневзве́шенное значе́ние — weighted mean value
    сре́днее значе́ние — mean, mean [average] value
    сре́днее значе́ние по всем состоя́ниям — value averaged over all states
    сре́днее арифмети́ческое значе́ние — arithmetical average, arithmetical mean
    сре́днее геометри́ческое значе́ние — geometrical mean
    среднеквадрати́чное значе́ние — root-mean-square [effective, rms] value
    стациона́рное значе́ние — steady-state [stationary] value
    установи́вшееся значе́ние — steady-state [stationary] value
    уточнё́нное значе́ние ( в методе последовательных приближений) — improved value
    характе́рное значе́ние — representative value
    целочи́сленное значе́ние — integral value
    ча́стное значе́ние — particular [special] value
    чи́сленное значе́ние — numerical value
    находи́ть чи́сленное значе́ние алгебраи́ческого выраже́ния — evaluate an (algebraic) expression
    значе́ние шкалы́, коне́чное — full scare value
    эффекти́вное значе́ние — effective [root-mean-square, rms] value

    Русско-английский политехнический словарь > значение

  • 31 установившееся возвращающееся напряжение постоянного тока

    1. d.c. steady-state recovery voltage

     

    установившееся возвращающееся напряжение постоянного тока
    Напряжение в цепи постоянного тока после исчезновения переходных явлений, выраженное средним значением при наличии пульсации.
    МЭК 60050(441-17-28).
    [ ГОСТ Р 50030. 1-2000 ( МЭК 60947-1-99)]

    EN

    d.c. steady-state recovery voltage
    the recovery voltage in a d.c. circuit after the transient voltage phenomena have subsided, expressed by the mean value where ripple is present
    [IEV number 441-17-28]

    FR

    tension de rétablissement en courant continu en régime établi
    tension de rétablissement dans un circuit à courant continu après la disparition des phénomènes transitoires de tension, exprimée par sa valeur moyenne s'il y a des ondulations
    [IEV number 441-17-28]

     

    EN

    • d.c. steady-state recovery voltage

    DE

    FR

    Русско-английский словарь нормативно-технической терминологии > установившееся возвращающееся напряжение постоянного тока

  • 32 установившееся возвращающееся напряжение постоянного тока

    1. wiederkehrende Dauergleichspannung

     

    установившееся возвращающееся напряжение постоянного тока
    Напряжение в цепи постоянного тока после исчезновения переходных явлений, выраженное средним значением при наличии пульсации.
    МЭК 60050(441-17-28).
    [ ГОСТ Р 50030. 1-2000 ( МЭК 60947-1-99)]

    EN

    d.c. steady-state recovery voltage
    the recovery voltage in a d.c. circuit after the transient voltage phenomena have subsided, expressed by the mean value where ripple is present
    [IEV number 441-17-28]

    FR

    tension de rétablissement en courant continu en régime établi
    tension de rétablissement dans un circuit à courant continu après la disparition des phénomènes transitoires de tension, exprimée par sa valeur moyenne s'il y a des ondulations
    [IEV number 441-17-28]

     

    EN

    • d.c. steady-state recovery voltage

    DE

    FR

    Русско-немецкий словарь нормативно-технической терминологии > установившееся возвращающееся напряжение постоянного тока

  • 33 установившееся возвращающееся напряжение постоянного тока

    1. tension de rétablissement en courant continu en régime établi

     

    установившееся возвращающееся напряжение постоянного тока
    Напряжение в цепи постоянного тока после исчезновения переходных явлений, выраженное средним значением при наличии пульсации.
    МЭК 60050(441-17-28).
    [ ГОСТ Р 50030. 1-2000 ( МЭК 60947-1-99)]

    EN

    d.c. steady-state recovery voltage
    the recovery voltage in a d.c. circuit after the transient voltage phenomena have subsided, expressed by the mean value where ripple is present
    [IEV number 441-17-28]

    FR

    tension de rétablissement en courant continu en régime établi
    tension de rétablissement dans un circuit à courant continu après la disparition des phénomènes transitoires de tension, exprimée par sa valeur moyenne s'il y a des ondulations
    [IEV number 441-17-28]

     

    EN

    • d.c. steady-state recovery voltage

    DE

    FR

    Русско-французский словарь нормативно-технической терминологии > установившееся возвращающееся напряжение постоянного тока

  • 34 амплитуда

    amplitude, ( импульса) height, magnitude, range, peak, span
    * * *
    амплиту́да ж.
    amplitude, peak value
    амплиту́да вероя́тности ( состояния) — probability amplitude
    амплиту́да вы́броса на и́мпульсе — pulse-spike amplitude
    де́йствующая амплиту́да — root-mean-square [rms, effective] amplitude
    амплиту́да и́мпульса — pulse amplitude, pulse height
    ко́мплексная амплиту́да — complex amplitude
    максима́льная амплиту́да — peak amplitude, crest value
    амплиту́да отклоне́ния — deviation amplitude
    амплиту́да отражё́нной волны́ — reflection amplitude
    амплиту́да переме́нного напряже́ния на се́тке — grid swing
    амплиту́да перехо́дного проце́сса — transient amplitude
    амплиту́да прили́ва — tidal range
    амплиту́да сбро́са геол. — fault throw
    амплиту́да сигна́ла на се́тке — grid swing
    амплиту́да смеще́ния по простира́нию геол. — horizontal strike amplitude of a fault
    сре́дняя амплиту́да — average amplitude
    сре́дняя, абсолю́тная амплиту́да — average absolute amplitude
    структу́рная амплиту́да — structure amplitude
    углова́я амплиту́да — angular amplitude
    удво́енная амплиту́да — peak-to-peak [double] amplitude
    установи́вшаяся амплиту́да — steady-state amplitude
    эффекти́вная амплиту́да — root-mean-square [rms, effective] amplitude

    Русско-английский политехнический словарь > амплитуда

  • 35 колебание(я)


    fluctuation, vibration
    (величины, напр., давления, напряжения) — fluctuation or vibration on each side of a mean value or position.
    - (периодический процесс) — oscillation
    -, вынужденные — forced oscillation
    -, вынужденное (вибрационнoe) — forced vibration
    вибрация от воздействия внешних периодически прилаженных сил, — when vibration results from the application of an external periodic force.
    -, высокочастотное ("зуд" поверхности управления) непрерывное колебание поверхности управления, вызываемое прерывистым отрывом воздушного потока. — buzz. sustained oscillation of a control surface caused by intermittent flow separation.
    -, высокочастотные ("зуд") элероны — aileron buzz
    -, изгибное — bending vibration
    -, крутильное — torsional vibration
    - лопасти несущего винта относительно вертикального шарнира — hunting angular oscillation of а rotor blade about the drag hinge.
    - напряжения — voltage fluctuation
    -, незатухающие — sustained oscillation
    -, неустановившиеся — transient vibration
    любое движение в вибрационной системе за период, потребный для перехода системы из одного условия приложения силы в другое, — any motion in a vibrating system which occurs during the time required for the system to adapt itself from one force condition to another.
    - оборотов — speed/rpm/ fluctuation, variation in rpm, speed variation
    - no крену — roll(ing) oscillation
    - no тангажу — pitch(ing) oscillation
    - подачи питания — power supply variations
    - показаний (указателя) — unstable display /reading/
    -, поперечное (самолета) — lateral oscillation
    любое движение, вызываемое периодическим изменением движения самолета по крену, рысканию и боковому скольжению. — any motion which is made up of а periodic variation of the rolling, jawing and side-slipping of an aircraft.
    -, принудительное — forced oscillation
    -, продольное (самолета) — longitudinal oscillation
    любое движение, вызываемое периодическим изменением скорости полета, высоты и угла тангажа. — any motion which is made up of а periodic variation of the flight speed, height and angle of pitch of an aircraft.
    -, продольное кратковременное — short-period longitudinal oscillation
    при данном виде колебаний поступательная скорость самолета остается практически неизменной, но возникают изменения угла атаки и пространственного положения ла. — in short-period oscillations the aircraft forward speed remains substantially constant, involving predominantly changes in the incidence and attitude.
    - рыскания — yawing oscillation
    -, свободное (собственное) — free vibration
    вибрационное движение в упругой системе, выведенной из состояния равновесия, и свободной от дальнейшего приложения внешней силы. — free vibration is the vibratory motion which takes place when an elastic system is displaced from its equilibrium position and released.
    -, скручивающие — torsional vibration
    - стрелки (прибора) — pointer oscillation
    - стрелки прибора (относительно отметки шкалы) стрелка должна возвратиться в нулевое положение, проходя через нулевую отметку не более двух раз. — crossing the pointer should return to zero without crossing the zero mark more than twice.
    - температуры — temperature variation
    -, установившееся (устойчивое) — steady-state vibration
    -, фугоидное — phugoid oscillation
    длинно-периодные колебания при нарушении продольнаго движения самолета. — а long-period oscillation characteristic of the disturbed longitudinal motion of an aeroplane.
    - шимми — shimmy
    вынужденные колебания самоцентрирующегося переднего колеса шасси относительно оси свободного ориентирования при движении по поверхности с повышенным коэффициентом трения. — а forced oscillation of a casfaring wheel about the castor axis when travelling on a surface the coefficient of friction of which exceeds a critical value.
    затухание к. стрелки (прибоpa) — damping of the pointer oscillation
    успокоение к. — oscillation damping
    гасить к. — damp oscillation

    Русско-английский сборник авиационно-технических терминов > колебание(я)

  • 36 длительный допустимый ток

    1. Strombelastbarkeit, f
    2. 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:

    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

  • 37 длительный допустимый ток

    1. current-carrying capacity
    2. continuous current-carrying capacity
    3. continuous current
    4. ampacity (US)

     

    (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:

    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

  • 38 длительный допустимый ток

    1. courant permanent admissible, m
    2. 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:

    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

  • 39 выравниваться

    •

    These forces level off at a high temperature.

    •

    The current increases with applied potential, until it levels off at a limiting value.

    * * *
    Выравниваться-- The erosion rate was initially high, but quickly leveled off to a steady-state rate.

    Русско-английский научно-технический словарь переводчика > выравниваться

  • 40 отставать на

    •

    The steady-state response lags behind the zero-inertia response by the following value:...

    Русско-английский научно-технический словарь переводчика > отставать на

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