O.M.D alarm is a safety Device which is provided in the main engine to prevent crankcase explosion. IT HAS A 6 SECONDS DELAY BEFORE SLOWING DOWN THE MAIN ENGINE TO 40% OF MCR.
WHEN THE O.M.D ALARM comes, First action is to check WHETHER THE ALARM IS FAULTY OR NOT. O.M.D ALARM IS USUALLY PROVIDED ONLY IN ECR. AS A RESULT, WE MUST FIRST DETERMINE FROM WHICH UNIT THE ALARM IS ISSUED. THE ALARM WAS THEN RESET. THE O.M.D ALARM SLOWS DOWN THE ENGINE AS A RESULT. IF SLOW DOWN OCCURS BEFORE YOU CAN RESET THE ALARM, THEN THE FUEL LEVER SHOULD BE PUT IN THE SLOW DOWN POSITION FIRST. VERIFY IF THE ALARM COMES FROM THE SAME UNIT AGAIN. IF YES, THEN FOLLOW THESE STEPS:-
Action taken in case of OMD Alarm Comes
- Inform the bridge and request to dead slow speed.
- Check trueness of alarm ( zero check ) and sensitivity. if all correct then put it in auto and if again comes then inform chief engineer.
- Request to stop main engine from bridge
- Stop main engine
- Cut off fuel supply and switch off the blower
- keep running the lube oil pump and the jacket cooling water pump
- ventilate the engine room by opening of skylight and prepare the fire fighting equipments.
- stop lube oil pump, and shut off starting air and engage the turning gear.
- after 20 minutes of stopping of engine, check by palm whether crankcase door is still hot or not. If hot then again wait for some time and then open the crankcase door.
- just slack open the crankcase door not to be open completely,just to check that crankcase is not pressurised from inside.
- now, enter into crarankase with torch and check the temperature of main bearings. if it is not more then it will give you white metal
- check temperature of the piston rod, stuffing box, crosshead, connecting rod, telescopic pipe.
- look out for blisterred paint, squeezed out bearing metal and discolatation caused by heat surfaces.
- locate the hot spot and rectify it
- start lube oil pump and check the flow of oil to the bearings
- disengage the turning gear and start the engine.
- stop engine after 15 minutes and again inspect for hot spots in crankcase
- again run engine for 1 hour and then after stopping again inspect crankcase.
- now. again run the engine on full load and inspect crankase and ensure that there is no fault.
after all the check and inspection , if you do not fight anything then check all omd alarms are working satisfactory or not.