SAE AMS7295/3 Radiographic Film, 4-80 (NONCURRENT Jul 1998)
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来源:标准资料网
Product Code:SAE AMS7295/3
Title:Radiographic Film, 4-80 (NONCURRENT Jul 1998)
Issuing Committee:Ams K Non Destructive Methods And Processes Committee
Scope:This specification covers one type of medium-contrast, fine-grain radiographic film in the form of cut sheets or rolls.
【英文标准名称】:Jewellery-Finenessofpreciousmetalalloys
【原文标准名称】:珠宝.贵重金属合金纯度
【标准号】:BSEN29202-1993
【标准状态】:现行
【国别】:英国
【发布日期】:1993-02-15
【实施或试行日期】:1993-02-15
【发布单位】:英国标准学会(BSI)
【起草单位】:BSI
【标准类型】:()
【标准水平】:()
【中文主题词】:化学成分;含钯合金;银合金;铂合金;金合金;珠宝
【英文主题词】:Alloys;Assay;Definition;Definitions;Fineness;Gold;Goldalloys;Jewellery;Materials;Noblemetals;Platinum;Platinumalloys;Silver;Silveralloys;Specifications
【摘要】:ThisInternationalStandardspecifiesarangeoffinenessofpreciousmetalalloys(excludingsolders)recommendedforuseinthefieldofjewellery.NOTE1Nationallegalrequirementsforthedesignation,markingandstampingoffinishedarticlesintherespec-tivecountrieshavetobetakenintoaccount.
【中国标准分类号】:Y88;H15
【国际标准分类号】:39_060
【页数】:8P;A4
【正文语种】:英语
【英文标准名称】:Short-circuitcurrentsinthree-phasea.c.systems-Part0:Calculationofcurrents
【原文标准名称】:三相交流系统短路电流第0部分：电流计算
【标准号】:IEC60909-0-2001
【标准状态】:现行
【国别】:国际
【发布日期】:2001-07
【实施或试行日期】:
【发布单位】:国际电工委员会(IX-IEC)
【起草单位】:IEC/TC73
【标准类型】:()
【标准水平】:()
【中文主题词】:三相电流;短路电流;交流电流;电流;电气工程;数学计算
【英文主题词】:Alternatingcurrent;Currents;Definitions;Electricpowernetworks;Electricalengineering;Electrically-operateddevices;Faultcurrents;Highvoltage;Lowvoltage;Mathematicalcalculations;Properties;Shortcircuitimpedance;Shortcircuits;Short-circuitcurrents;Symbols;Three-phasecurrent;Three-phasenetworks
【摘要】:ThispartofIEC60909isapplicabletothecalculationofshort-circuitcurrents:·inlow-voltagethree-phasea.c.systems·inhigh-voltagethree-phasea.c.systemsoperatingatanominalfrequencyof50Hzor60Hz.Systemsathighestvoltagesof550kVandabovewithlongtransmissionlinesneedspecialconsideration.ThispartofIEC60909establishesageneral,practicableandconciseprocedureleadingtoresults,whicharegenerallyofacceptableaccuracy.Forthiscalculationmethod,anequivalentvoltagesourceattheshort-circuitlocationisintroduced.Thisdoesnotexcludetheuseofspecialmethods,forexamplethesuperpositionmethod,adjustedtoparticularcircumstances,iftheygiveatleastthesameprecision.Thesuperpositionmethodgivestheshort-circuitcurrentrelatedtotheoneloadflowpresupposed.Thismethod,therefore,doesnotnecessarilyleadtothemaximumshort-circuitcurrent.ThispartofIEC60909dealswiththecalculationofshort-circuitcurrentsinthecaseofbalancedorunbalancedshortcircuits.Incaseofanaccidentalorintentionalconductivepathbetweenonelineconductorandlocalearth,thefollowingtwocasesmustbeclearlydistinguishedwithregardtotheirdifferentphysicalpropertiesandeffects(resultingindifferentrequirementsfortheircalculation):·line-to-earthshortcircuit,occurringinasolidlyearthedneutralsystemoranimpedanceearthedneutralsystem;·asingleline-to-earthfault,occurringinanisolatedneutralearthedsystemoraresonanceearthedneutralsystem.Thisfaultisbeyondthescopeof,andisthereforenotdealtwithin,thisstandard.Forcurrentsduringtwoseparatesimultaneoussingle-phaseline-to-earthshortcircuitsinanisolatedneutralsystemoraresonanceearthedneutralsystem,seeIEC60909-3.Short-circuitcurrentsandshort-circuitimpedancesmayalsobedeterminedbysystemtests,bymeasurementonanetworkanalyzer,orwithadigitalcomputer.Inexistinglow-voltagesystemsitispossibletodeterminetheshort-circuitimpedanceonthebasisofmeasurementsatthelocationoftheprospectiveshortcircuitconsidered.Thecalculationoftheshort-circuitimpedanceisingeneralbasedontherateddataoftheelectricalequipmentandthetopologicalarrangementofthesystemandhastheadvantageofbeingpossiblebothforexistingsystemsandforsystemsattheplanningstage.Ingeneral,twoshort-circuitcurrents,whichdifferintheirmagnitude,aretobecalculated:·themaximumshort-circuitcurrentwhichdeterminesthecapacityorratingofelectricalequipment;and·theminimumshort-circuitcurrentwhichcanbeabasis,forexample,fortheselectionoffuses,forthesettingofprotectivedevices,andforcheckingtherun-upofmotors.NOTEThecurrentinathree-phaseshortcircuitisassumedtobemadesimultaneouslyinallpoles.Investigationsofnon-simultaneousshortcircuits,whichmayleadtohigheraperiodiccomponentsofshort-circuitcurrent,arebeyondthescopeofthisstandard.Thisstandarddoesnotcovershort-circuitcurrentsdeliberatelycreatedundercontrolledconditions(short-circuittestingstations).ThispartofIEC60909doesnotdealwiththecalculationofshort-circuitcurrentsininstallationsonboardshipsandaeroplanes.
【中国标准分类号】:K04
【国际标准分类号】:17_220_01
【页数】:137P.;A4
【正文语种】:英语
