轮机英语（二三管轮）Lesson 24 AC Generator.pptx

MarineEngineeringEnglish《轮机英语》APracticalCourseforEngineersWorkingonBoardShips

MarineElectricalSystemandAutomatizationLesson24ACGenerator第24课交流发电机

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

4part1NewWordsandExpressions

5part2TextAnalysis

Lesson24ACGeneratorAlternatingcurrenthasnowallbutreplaceddirectcurrentasthestandardsupplyforallmarineinstallations.#交流电现在几乎取代了直流电，成为所有海上设施的标准电源。

Lesson24ACGeneratorTheuseofalternatingcurrenthasanumberofimportantadvantages:forexample,reducedfirstcost,lessweight,lessspacerequiredandareductioninmaintenancerequirements.#使用交流电有许多重要的优点：例如，降低了初始成本、重量、所需空间和维护要求。

Lesson24ACGeneratorDirectcurrentdoes,however,offeradvantagesinmotorcontrolusing,forexample,theWard-Leonardsystemwhichprovidesawiderangeofspeed.#然而，直流电确实在电机控制方面具有优势，例如，沃德·伦纳德系统提供了广泛的速度范围。

Directingcurrentgenerator直流发电机工作原理9

Alternatingcurrentgenerator交流发电机工作原理

Lesson24ACGeneratorAcoilofwirerotatinginamagneticfieldproducesacurrent.#线圈在磁场中旋转产生电流。

Lesson24ACGeneratorThecurrentcanbebroughtouttotwoslipringswhichareinsulatedfromtheshaft.#电流可由与轴绝缘的滑环输出。

Lesson24ACGeneratorCarbonbushesrestontheseringsastheyrotateandcollectthecurrentforuseinanexternalcircuit.#碳刷停靠在旋转的滑环上，汇集电流供外电路使用。

Lesson24ACGeneratorCurrentcollectedinthiswaywillbealternating,thatis,changingindirectionandrisingandfallinginvalue.#以这种方式汇集的电流是交变的，即方向变化且数值升降。

Lesson24ACGeneratorToincreasethecurrentproduced,additionalsetsofpolesmaybeintroduced.#为了增加输出的电流可以采用多组磁极。

Lesson24ACGeneratorThemagneticfieldisprovidedbyelectromagnetssoarrangedthatadjacentpoleshaveoppositepolarity.#磁场是由电磁铁产生，电磁铁布置成相邻的磁极磁性相反。

Lesson24ACGeneratorThese“fieldcoils”,as