轮机英语（二三管轮）Lesson 25 Paralleling Operation.pptx

MarineEngineeringEnglish《轮机英语》APracticalCourseforEngineersWorkingonBoardShips

MarineElectricalSystemandAutomatizationLesson25ParallelingOperationofAlternators第25课交流发电机并车

LearningObjectives:1.Graspsomeusefulwordsandexpressionsinthewholetext.2.Afterstudyingthelesson,heorshewillhaveabetterunderstandingofParallelingOperationofAlternators.3

4part1NewWordsandExpressions

5part2TextAnalysis

Lesson25ParallelingOperationThreephasealternatorsarrangedforparalleloperationrequireaconsiderableamountofinstrumentation.#三相交流发电机的并车操作需要很多仪表。

Lesson25ParallelingOperationThiswillincludeammeters,watt-meters,voltmeters,frequencymetersandasynchronizingdevice.#包括电流表、功率表、电压表、频率表和同步指示装置。

Lesson25ParallelingOperationReversepowerprotectionisprovidedtoalternatorssincecurrentprotectioncannotbeused.#因不能采用逆电流保护，所以发电机装设了逆功率保护。

Lesson25ParallelingOperationAlternativelyvarioustripsmaybeprovidedintheeventofprimemoverfailuretoensurethatthealternatordoesnotactasamotor.#或者装设各种脱扣机构，万一在原动机故障时，确保发电机不能按电动机工作。

Lesson25ParallelingOperationTheoperationofparallelingtwoalternatorsrequiresthevoltagestobeequalandalsoinphase.#发电机并车运行需要电压相等且同相。

Lesson25ParallelingOperationThealternatingcurrentoutputofanymachinesisalwayschanging,sofartwomachinestooperatetogethertheirvoltagesmustbechangingatthesamerateorfrequency,andmustbereachingtheirmaximum(oranyothervalue)together.#交流输出总是在改变，因此，对欲并车的两台发电机而言，它们的电压必须以相同的变化率或频率变化，并且必须同时达到最大值(或其它值)。

Lesson25ParallelingOperationTheyarethensaidtobe“inphase”.#此时我们就说它们“同相”。

Lesson25ParallelingOperationUseisnowadaysmadeofasynchroscopewhenparallelingtwoACmachines.#现今，当进行并车时使用同步指示器。

Lesson25ParallelingOperationThesynchroscopehastwowindingswhichareconnectedonetoeachsideoftheparallelingswitch.#同步指示器有两组绕组，每组与并车开关一侧相连。

Lesson25ParallelingOperat