欢迎来到天天文库
浏览记录
ID:61521003
大小:272.00 KB
页数:96页
时间:2021-02-11
《轮机英语课件lesson29.ppt》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、LESSON29CONTROLSYSTEMS(DIESELENGINEBRIDGECONTROLSYSTEM)IIJimeiuniversityFig.9showsthebasicrequirementsforstartingandcontrolofadirectreversingslowspeeddieselengine.JimeiuniversityThebasiccontrolloopfordieselengineisofclosedloopformwithatwoor,three-termcontroller,possiblywithaloadlimitingde
2、viceandalarm,controllingtheenginespeed.JimeiuniversityDesiredvaluesignalsforenginerpmaretransmittedfromthebridgecontrolpositionorengineroomremotecontrolpositionandJimeiuniversityandcomparedwiththemeasuredvaluesignalfromapropellershaftspeedsensor,thedifferencebetweenthesetwosignalsbeingthe
3、rpmdeviationfromtherequired.JimeiuniversityThiserrorsignalisthenusedbythecontrollertoadjustthefuelrackstoreturntheenginespeedtothatrequired.JimeiuniversityElectronic,electro-pneumatic,electro-hydraulicandpneumaticsystemsmaybeusedforsignaltransmissionandfuelrackoperation.JimeiuniversityThe
4、directionofrotationrequiredisachievedbymovingaleverinahorizontalslot,Jimeiuniversitymovementtoeitherextremeoperatingthevalvescontrollingtheservo-motorwhichpositionsthecamshaftforthecorrectairstartandfuelvalvetimingfortherequireddirectionofrotation.JimeiuniversityTheleveristhenmovedinavert
5、icalslot,theinitialmovementactuating(操纵、驱动)thestartingsequenceonairandJimeiuniversityandwhenapre-setrpmhasbeenreached(30r/minforexample)theairistripped(切断)andfuelapplied.JimeiuniversitySubsequent(后续的)movementoftheleveroperatesaservo-mechanismwhichadjuststhespeedsettingleverontheengineandw
6、hichisinturnconnectedtothegovernor.JimeiuniversityThestartingsequenceismonitoredbytheinterlockandcheckcircuitsshown,andaprogrammer(程序控制器).JimeiuniversityThisallowsthemaximumaccelerationtocommensuratewith(与…相应)safeoperationalrequirementsoftheenginewhilstmanoeuvringbutpreventsengineoverload
7、ing.JimeiuniversityItalsoprogrammestheincreaseinpowerwhenmovingfromFullAheadtoFullAway,guardingagainstexcessivepowerdemandsandpropellercavitation(空洞、气蚀)andcriticalspeedslipping.JimeiuniversityForcrashmanoeuvres(应急操作)theleverismovedfromoneextremetotheother,thesequenc
此文档下载收益归作者所有