第三章 三相交流电路

为搞好山东省交通科学研究所研发基地项目的结算审计工作,我跟踪审计部特针对本项目作如下要求,请各施工单位、供货单位遵照执行：andperformancetestcopiesoftherecord.Ifnecessary,reviewshouldbecarriedout;4)forspringhangers(includedsimplespring,hangersandconstantsupporthangers)itshouldalsoberecognizedassettingandlockingofloads.5)checkthesurfacequality,foldedlayeringandwithoutcracks,rustandotherdefects.5)aftercompletionofthetestandcontroldrawingnumberonebyone,byseriesbaled.Coloralloysteelparts,thepartsmarkinginstallationlocationandrotationaboutthedirectionyouwant.7.3.14.hangersinstallation7.3.14.1hangerlayouta.acleardesignofhangershouldbeinstalledstrictlyinaccordancewiththedrawingsanddesignsshallnotbeinstalledwrong,missing,etc.B.ownarrangementofpipingsupportandhangersetandselectionshouldbebasedoncomprehensiveanalysisofgenerallayoutofpipingsystems;coldinstallationofsteampipewithparticularattentionreservedforcompensationofthermalexpansiondisplacementandorientation.C.supportsystemsshouldberationaltowithstandpipeloads,staticloadandincidentalload;reasonablepipingdisplacement;guaranteedundervariousconditions,stressarewithintheallowedrange.Strength,stiffness,andmeetrequirementstopreventvibrationandsoothingwater,withoutaffectingtheadjacentequipmentmaintenanceandotherpipinginstallationandexpansion.D.equipmentconnectedtotheinterfacetomeetpipelinethrust(torque)limitrequirements;increasethestabilityofpipingsystemstopreventpipeline...Tubewallthickness(mm)2-34-67-10weldformnoslopemouthweldstrengtheningheighth(mm)1-1.51.5-2weldwidthb(mm)5-67-6hasslopemouthweldstrengtheningheighth(mm)1.5-22weldwidthb(mm)coverhadeachedgeslopemouthabout2mmargonarcweldingweldstrengtheningsurfaceheightandwidthtubewallthickness(mm)2--33--45--6weldformweldstrengtheningheighth(mm)1-1.51.5-22-2.5widthb(mm)第3章三相交流电路3.1三相交流电源判断题1.三相电源的相序就是交流电的瞬时值到达最大值的顺序。（√）2.三相电源有正序（顺序）和反序（逆序）之分。（√）3.相线与中性线之间的电压称为相电压。（√）4.相线与相线之间的电压称为线电压。（√）5.相线与中性线之间的电压称为线电压。（×）6.相线与相线之间的电压称为相电压。（×）7.三相四线制电源中，相电压等于线电压的3倍。（×）8．三相四线制电源中，线电压等于相电压的3倍。（√）9.线电压是指火线与零线之间的电压。（×）10.相电压是指火线与零线之间的电压。（√）11.三相对称电压就是三个频率相同、幅值相等、相位互差120°的三相交流电压。（√）选择题1．(2分)已知对称三相电源的相电压uA=10sin(ωt+60°)V，相序为A-B-C，则当电源星形联接时线电压uAB为_____V。A.10sin(ωt+90°)B.17.32sin(ωt+90°)C.17.32sin(ωt-30°)D.17.32sin(ωt+150°)正确答案是B，本题涉及的知识点是：三相交流电源线电压与相电压的关系。2．(2分)对称正序三相电源作星形联接，若相电压uB=100sin(ωt-30°)V，则线电压uAB=__V。A.1003sin(ωt+120°)B.1003sin(ωt-60°)C.1003sin(ωt-150°)D.1003sin(ωt-150°)正确答案是A，本题涉及的知识点是：三相交流电源线电压与相电压的关系。3．(2分)在正序对称三相电压中，uA=U2sin(ωt-90°)，则接成星形时，其线电压uAB为_____。U6sin(ωt+30°)U6sin(ωt-60°)U2sin(ωt-30°)U2sin(ωt+60°)为搞好山东省交通科学研究所研发基地项目的结算审计工作,我跟踪审计部特针对本项目作如下要求,请各施工单位、供货单位遵照执行：andperformancetestcopiesoftherecord.Ifnecessary,reviewshouldbecarriedout;4)forspringhangers(includedsimplespring,hangersandconstantsupporthangers)itshouldalsoberecognizedassettingandlockingofloads.5)checkthesurfacequality,foldedlayeringandwithoutcracks,rustandotherdefects.5)aftercompletionofthetestandcontroldrawingnumberonebyone,byseriesbaled.Coloralloysteelparts,thepartsmarkinginstallationlocationandrotationaboutthedirectionyouwant.7.3.14.hangersinstallation7.3.14.1hangerlayouta.acleardesignofhangershouldbeinstalledstrictlyinaccordancewiththedrawingsanddesignsshallnotbeinstalledwrong,missing,etc.B.ownarrangementofpipingsupportandhangersetandselectionshouldbebasedoncomprehensiveanalysisofgenerallayoutofpipingsystems;coldinstallationofsteampipewithparticularattentionreservedforcompensationofthermalexpansiondisplacementandorientation.C.supportsystemsshouldberationaltowithstandpipeloads,staticloadandincidentalload;reasonablepipingdisplacement;guaranteedundervariousconditions,stressarewithintheallowedrange.Strength,stiffness,andmeetrequirementstopreventvibrationandsoothingwater,withoutaffectingtheadjacentequipmentmaintenanceandotherpipinginstallationandexpansion.D.equipmentconnectedtotheinterfacetomeetpipelinethrust(torque)limitrequirements;increasethestabilityofpipingsystemstopreventpipeline...Tubewallthickness(mm)2-34-67-10weldformnoslopemouthweldstrengtheningheighth(mm)1-1.51.5-2weldwidthb(mm)5-67-6hasslopemouthweldstrengtheningheighth(mm)1.5-22weldwidthb(mm)coverhadeachedgeslopemouthabout2mmargonarcweldingweldstrengtheningsurfaceheightandwidthtubewallthickness(mm)2--33--45--6weldformweldstrengtheningheighth(mm)1-1.51.5-22-2.5widthb(mm)正确答案是B，本题涉及的知识点是：三相交流电源线电压与相电压的关系。4.(2分)对称正序三相电源作星形联接，若相电压uA=100sin(ωt-60°)V，则线电压uBC=______V。A.100sin(ωt+90°)B.1003sin(ωt+90°)C.1003sin(ωt-150°)D.100sin(ωt-150°)正确答案是C，本题涉及的知识点是：三相交流电源线电压与相电压的关系。5．（2分）三相四线制电源能输出种电压。A.1B.2C.3D.4正确答案是B，本题涉及的知识点是：三相交流电源提供电压的类型。6．(2分)在正序三相交流电路中，接有三相对称负载，设A相电流为iA=ImsinωtA，则iB为：A。A.iB=Imsin(ωt-120°)AB.iB=ImsinωtAC.iB=Imsin(ωt-240°)AD.iB=Imsin(ωt+120°)A正确答案是A，本题涉及的知识点是：三相交流电源相电流之间的关系。7．(2分)三相电源相电压之间的相位差是120°，线电压之间的相位差是。A.60°B.90°C.120°D.180°正确答案是C，本题涉及的知识点是：三相交流电源线电压之间的关系。8．(2分)已知对称三相电源的相电压uB=10sin(ωt-60°)V，相序为A─B─C，则电源作星形联接时，线电压uBC为_____V。A.10sin(ωt+90°)B.103sin(ωt-90°)C.103sin(ωt-30°)D.103sin(ωt+150°)正确答案是C，本题涉及的知识点是：三相交流电源线电压之间相序的关系。3.2负载星形连接的三相交流电路判断题1．当三相电源对称，负载特也对称时，中线电流为０，因而可以取消中线。（√）2.对称星形三相电路中，线电压与相电流间的相位差等于线电压与线电流间的相位差。（√）3．对称三相感性负载（星形接法）接于线电压380Ｖ的三相对称电源上，若每相负载电阻