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ID:46583536
大小:825.00 KB
页数:170页
时间:2019-11-25
《轮机英语多媒体课件33》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、第三章船舶电气与船舶安全1886Thestaringcurrentofana.c.motoris______theratedcurrent.交流电机的启动电流比额定电流大得多。A.thesameasB.muchlargerthanC.lessthanD.equals1887Ammeteristomeasurethe______安培表用来测量电流。A.currentB.voltageC.powerD.frequencyInamodemthree-phaseA.C.synchronousbrushesgene
2、rator,theexcitationwindingisontherotor.Thatmeans______对于现代三相交流同步有刷的发电机,励磁线圈在转子上。意即转子上的线圈用于输入励磁电流。A.ThegeneratorneednotexcitationB.ThewindingontherotorisforinputtingexcitationcurrentC.TherearethreephasewindingsontherotorD.Thegeneratorhasbrushes1889Theoverc
3、urrentrelay______themotorcontactorwhenthemotorexceedsitsratedcurrent.当电动机超过额定电流时,过电流继电器将跳开。A.connectsB.tripsC.foulsD.destructs1886B1887A1888B1889BThe______isameasureofthephasedifferencebetweenvoltageandcurrentandisexpectedasthecosineofphaseangle.功率因数可用来表示
4、电压与电流之间的相位差,表达成相位角的余弦。A.powerB.efficiencyC.effectivepowerD.powerfactor1891Currentchangingindirectionandrisingandfallinginvalueis______方向、大小都变化的电流是交流电。A.A.C.B.D.C.C.generatorD.freshwatergenerator1892Theoperationofparallelingtwoalternatorsrequiresthevoltage
5、stobe______andalsoinphase.两台交流发电机并联,需要电压相等,并且同相。A.zeroB.eliminatedC.differentD.equal1893The______,cagerotorinductionmotoristhefirstchoicemarinemotorinmostmodemshipsbecauseofitselectricalandmechanicalsimplicity.现代船舶上使用的电机都是三相电机。A.singlephaseB.twophaseC.thr
6、eephaseD.fourphase1894Thestar-deltastarterisaneffectivemethodof______voltagestartingofamotor.采用Y—△启动器是电饥低电压启动的最好方法。A.increasedB.reducedC.unchangedD.Noneoftheabove1890D1891A1892D1893C1894BWitha______loadthevoltageandcurrentareinphase.对于纯电阻负荷,电压和电流同相。A.pure
7、lyresistanceB.capacitiveC.inductiveD.Noneoftheabove1896Increasingthetemperatureofafuelwill______itsviscosity.提高燃油的温度将降低其粘度。A.increaseB.reduceC.keepD.Noneoftheaboveistrue.1897The______isusedtomeasurethevolumeofaliquidorgasthroughapipelinwithinanygivenperio
8、doftime.流量计用于测量在给定时间内,通过管子的液体或气体的体积。A.flowmeterB.viscometerC.micrometerD.feeler1898"gaugepressure"means______“表压”即是“超过大气压的压力”。A.vacuumB."theexcessofpressureaboveatmosphere"C."figureonagauge"D.Anyoftheabove1899Amanom
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