轮机英语周考

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1、2141Whenworkingonahighvoltagecircuit,youshouldalwayshaveanotherpersonpresentwithyou.Thispersonshouldhaveagoodworkingknowledgeof_____A.thecircuitbeingworkedonandthelocationofallswitchesandcircuitbreakerscontrollingitB.first-aidtechniquesfortreatingelectricalshockC.cardiopulmonary

2、resuscitation(CPR)D.Alloftheabove2140Anemergencygenerator,drivenbyaninternalcombustionengine,shallbetestedunderloadforaminimumof2hoursatleastonceevery_____A.weekB.2weeksC.monthD.3months2137ThemostcommontypeofACservicegeneratorfound~shipisthestationary_____A.electromagneticfield,

3、revolvingarmaturetypeB.electromagneticfield,oscillatoryarmaturetypeC.armature,oscillatoryelectromagnetfieldtypeD.armature,rotatingelectromagneticfieldtype2134TheenergyconsumedbyanACmotor,asstrictlyreactivepower,is_____。A.usedtodomechanicalworkB.usedtoestablishthemagneticfieldoft

4、hemotorC.lostasheatgeneratedbythewindingsD.lostindoingworktoturnthemotoritself2131UniversalmotorswilloperateonACorDCcurrent,andaregenerallyfoundin_____A.portabletoolsB.largepumpmotorsC.turboelectricmainmotorsD.forceddraftfans2132Amotorenclosurewhichprotectsagainstfallingliquidsi

5、sclassifiedas_____A.waterproofB.dripproofC.spraytightD.sprayproof2127Sparkingatthebrushesofarunningmotorcouldbeanindicationof_____A.normaloperationB.adirtycommutatorC.increasedbrushcapacityD.watervaporabsorption2126IfaDCmotorrunshot,thecausemaybe____A.highmicaconditionB.lowambie

6、nttemperatureC.cloggedventilationductsD.anopenintheshuntfield2123InordertochangethedirectionofrotationofaD.C.motor_____①thefieldleadsmustbechanged;②theinputleadsmustbechangedA.①onlyB.②onlyC.either①or②D.both①and②2120Inanalternatingcurrentelectricalsystem,alowsystempowerfactorisad

7、irectsignof_____A.wastedenergyB.efficientoperationC.ashortintheexciterfieldwindingsD.anexcessivenumberofminorsystemgrounds2116PriortoclosingthebreakerwhenparallelingtwoACgenerators,therecommendedpracticeistohavethefrequencyoftheincomingmachine_____、A.slightlylessthanthelinefrequ

8、encyB.thesameasthelinefrequencyC.slightlygreate