according to the PMS. There are no tests or inspectionsrelated to SSS clutch assemblies, unless you areassigned to a CG-47 class ship. Remember, thatparticular type of SSS clutch has an internal PT brakeassembly. The ship’s maintenance action planperiodically requires that an inspection of the discassembly be made and the clearances between the discsmeasured.Additionally, you must check the externallymounted PT and shaft brake assemblies on a regularbasis according to the PMS. These inspectionsnormally include checking the brake pad thicknessmeasurements, rotor condition, proper operation of airor hydraulic actuators, and proper lubrication of vitalmoving parts.TROUBLESHOOTINGBecause SSS clutches are reliable, problems thatrequire troubleshooting are usually minimal. Like allother gear-driven assemblies, SSS clutches have atendency to wear and produce noise with age. Normalfailures are usually limited to faulty position indicatorswitches and failures related to the PT brake assemblies.We will not dwell on the clutch assemblies, but move onto some of the problems related to the installed brakeassemblies and the ways in which you, the GSsupervisor, can better identify them.The basic operation of both the PT and shaft brakesis the same as the disc brake system installed in mostautomobiles. All brake systems require some type ofmedium (air, oil, or air and oil) to force the caliper pistonagainst the brake pad which, in turn, is pushed againstthe disc. This action slows the rotation of the disc untilthe disc stops. Next are some common malfunctionsthat may occur in this system and ways that you canisolate the cause.Failure to EngageThere are several problems that can cause a braketo fail to engage. You must understand the operatingprinciples associated with the system. First, check tosee if there is sufficient air or oil pressure for operation.It is pretty obvious that if the activating medium (air oroil) is missing, this condition should produce an alarmat the console.Once you determine that the activating medium isavailable, you should try the manual control. If themanual control works, you should consider an electricalfault as the problem source. If the manual control doesnot work, you should continue troubleshooting. If thepressure regulator is not working, the supply cutoutvalve (if installed) may be closed, or there may be ablockage or leak in the supply line. These are allpossible causes for the failure. The last possibility tocheck is the electrical control. Did the brake actuallyengage? If the brake engages, but you do not receive abrake engaged indication, just look at the PT speed toverify a slowing down or a stop. If the PT has stopped,your indicator light may be out or the indicator switchmay be bad. If the PT does not stop, you may need helplocating where the command signal is lost.Failure to ReleaseWhen a brake fails to release, the three mostcommon causes are a command problem, a bad positionindicator switch, or a bad indicator light. If none ofthese are the cause, you should check for a bindingcaliper and weak or damaged return springs.Failure to Stop RotationWhen the brake applies but does not stop rotation,the most common causes are insufficient actuatingpressure, contaminated brake pads, a damaged rotor(disc), or a binding caliper piston.ALIGNMENTS AND ADJUSTMENTSBasically, the only components that have anyadjustments or alignment checks are the PT and shaftbrake systems. Normally, all of these adjustments oralignments are performed as requirements resultingfrom a PMS inspection.REMOVAL AND REPLACEMENT OFCOMPONENTSThe removal and replacement of a clutch maybeperformed by your ship’s personnel if there is sufficienttime or if a casualty occurs. Most of the time, however,the engineer officer will opt to have an outside activityperform the work.On the other hand, the brakes and their subsystemscan be easily maintained by your ship’s maintenancetechnicians and personnel.LINE SHAFT (SPRING) BEARINGSThe line shaft (spring) bearings are self-aligning,oil-lubricated journal bearings. Each bearing is aself-contained assembly with its own oil reservoir thatcontains 2190 TEP oil.3-10
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