【英文标准名称】:Outlineofinvestigationforprotectorsforantennalead-inconductors
【原文标准名称】:天线引入导线用保护器调查大纲
【标准号】:ULSUBJECT497E-2011
【标准状态】:现行
【国别】:美国
【发布日期】:2011-01-25
【实施或试行日期】:
【发布单位】:美国保险商实验所(US-UL)
【起草单位】:
【标准类型】:()
【标准水平】:()
【中文主题词】:
【英文主题词】:
【摘要】:1.1ThisOutlineofInvestigationcoversprotectorsforantennalead-inconductors.Thesedevicesareusedtolimitsurgesonthecablethatconnectstheantennatothereceiver/transmitterelectronicsandareconnectedbetweentheconductorsandthegroundedshieldorothergroundconnection.Typicalapplicationsincludeantennainstallationsforradioandtelevisionreceivingequipment,amateurradiotransmittingandreceivingequipment,cellulartelephonetowersandWiMaxorWiFiwirelessnetworks.1.2Ascoveredbytheserequirements,protectorsforantennalead-inconductorstypicallyconsistsofairgaparresters,gastubearresters,solid-statearrestersorquarter-wavestubtypedevices,orcombinationsofthesedevices.Othertechnologiesarenotexcluded.Theymayormaynotcontainadditionalcomponentssuchasinductorsorblockingcapacitors.Theseprotectorsareintendedtoprotectequipment,wiring,andpersonnelatthepremisesagainsttheeffectsofexcessivepotentialsandcurrentsontheconductorscausedbylightning.1.3Thesedevicesoperatetodivertasurgecurrenttoearth,andcontroltheresidualvoltage(alsoknownaslet-throughvoltage)toasuitablelevel.Oncethesurgecurrenthassubsided,thedeviceautomaticallyreturnsnormaloperationandresettoastatereadytoreceivethenextsurge.Residualvoltagelimitsortheirsuitabilitytominimizedamagetoconnectedequipmentisnotwithinthescopeoftheserequirements.1.4Theseprotectorsareinvestigatedfortheirmaximumdischargecurrent(Imax)capabilityusingan8/20currentwaveform.Thisisthemaximumimpulsecurrenttheprotectorcanwithstand,includingafterenvironmentalconditioning,withoutaffectingitssurgelimitingcapabilityorcreatingariskoffire,fragmentationorelectricalshock.1.5ThisOutlinedoesnotcoverthefollowing:a)Lightningprotectivedevicesfortheprotectionofsecondarydistributionwiringsystemsandequipment.b)AntennadischargeunitsforradioandtelevisionreceivingappliancesthatarecoveredbytheStandardforAntenna-DischargeUnits,UL452.c)Lightningconductorandairterminalsforconnectionoflightningrodsforbuildingprotection.d)ProtectorsforfirealarmsignalingcircuitsthatarecoveredbytheStandardforProtectorsforDataCommunicationsandFire-AlarmCircuits,UL497B.e)EquipmentcoveredbytheStandardforSecondaryProtectorsforCommunicationsCircuits,UL497A.f)EquipmentcoveredbytheStandardforSurgeProtectiveDevices,UL1449.g)EquipmentcoveredbytheStandardforProtectorsforPaired-ConductorCommunicationsCircuits,UL497.h)EquipmentcoveredbytheStandardforProtectorsforCoaxialCommunicationsCircuits,UL497C.i)DCblockingconnectorsorcomponentsthatdonothavelightningprotectionastheirprimaryfunction.j)Applicationswherefollow-oncurrentsmayoccur,suchasinstallationswherecommunicationswiringisroutedonsharedfacilitieswithelectricaldistributionsystems.1.6Specialinstallationmethodsarerequiredforequipmentconnectedtowire-linecommunicationfacilitiesservinghigh-voltageelectricpowerstationsoperatingatgreaterthan1kV.Theserequirementsdonotcovertheequipmentordevicesusedinthedesignofsuchinstallations.Specialsystemdesignrequirements,suchasthosecoveredbyRecommendedPracticefortheProtectionofWire-LineCommunicationFacilitiesServingElectricPowerLocations,IEEE487,shallbefollowedtoreducetherisksassociatedwithwire-linecommunicationfacilitiesservingsuchpowerstations.
【中国标准分类号】:M51
【国际标准分类号】:
【页数】:28P.;A4
【正文语种】:英语

标准名称：	建设工程劳动定额 市政工程-维修养护工程
替代情况：	替代LD/T 99.13-1997
发布部门：	人力资源和社会保障部
发布日期：	2009-01-08
实施日期：	2009-03-01
首发日期：
作废日期：
出版日期：

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