Generator Set, volume 2. These procedures providedetailed engine and interference removal instructions.These instructions should be strictly followed due to thevast differences in removal procedures between apropulsion GTE and an SSGTG.You must use the same planning skills andengineering practices in a GTG engine changeout as youuse in an LM2500 GTE changeout. The same strictapplication of safety precautions and following oftechnical manual procedures apply to every GTG enginechangeout.COOPERATIONShip’s readiness is the common purpose in thechangeout evolution.All personnel involved shouldshare a common commitment in achieving that purpose.A willingness by each individual to submerge his or herpersonal interest in favor of getting the job done is anecessary prerequisite to cooperation. You may have toadjust working hours and watch-standing duties to meetchangeout schedule requirements. Personnel may beassigned to duties they do not want to perform.Emphasize each individual’s importance, willingness,and contribution to the evolution. Engine changeout isan opportunist y to display your professional abilities asa leader and technicianMAINTENANCE TIPSAs a GS supervisor you will be responsible for theproper completion of most maintenance procedures.This section will cover some maintenance tips that canhelp you to understand the critical relationship betweenmaintenance performance and the proper operation ofthe LM2500. Remember, the contents of this section areFOR TRAINING PURPOSES ONLY and should inno way replace the use of the PMS or the manufacturer’smaintenance procedures.PLA RIGGINGIf the PLA is replaced for whatever cause, the PLArig check (mechanical and electrical) must beaccomplished. If the main fuel control (MFC) rig pindoes not fit properly (too loose, too tight, or can’t befully inserted), re-rig the PLA. Always comply with thePLA electrical rig check after you are assured that thethrottle command voltages are properly set (idle and fullthrottle).MechanicalThe key to a successful mechanical rigging is aproper alignment.Remember, although the PLAactuator arm is mechanically linked to the MFC leverarm, the PLA is electrically driven. The slightestmechanical restriction (binding) may cause incorrectPLA movement during engine operation. PLAmovement is most sensitive to a restriction when ineither engine speed or torque, and/or shaft torquelimiting condition. If a possible restriction is suspected,advance and retard the PLA electrically and check forany hesitation or jerking during travel. If hesitationexists, there may be a mechanical restriction.ElectricalThe normal process for this rigging will be checkingdc voltages at idle and full throttle positions. However,the moment the throttle is moved out of idle, indicatedtorque will go to midrange and oscillate. For example,on the DD-963/DDG-993 class ships, if mid-torqueoscillations are accompanied by an overtorqueindication and a PLA failure indication, then anotherproblem exists.Why?When the PLA is at idle, there is a PT5.4 biasthat assures PT5.4 is greater than PT2 for engine startpurposes. During PLA electrical rigging, the bias dropsout when the throttle is advanced.If PT5.4 is several tenths of a pound less than PT2,the torque computer goes berserk. But, PLA riggingmay be continued by pressing the BATTLEOVERRIDE button.However, suppose you have just been informed thatthe PT5.4 transducer requires calibration When thetorque goes berserk as described, immediately dial upP T5.4 and PT2 on the respective DDIs. PT5.4 will belower than PT2, thus requiring the activation ofBATTLE OVERRIDE to continue. This lower readingtells you the PT5.4 transducer requires calibration.VSV FEEDBACK CABLE RIGGINGWhyisitaccomplished?Whyisitimportant?VSV feedback cable rigging is necessary becausewe are “timing” a pilot valve inside the MFC so thecorrect vane angle is obtained for a given CIT/gasgenerator speed day. Actually, we are assuring that thepilot valve is timed to close off high pressure fuel flowto both the ROD END and the HEAD END pressure2-32
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