轮机英语多媒体课件33

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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