@catboy
Active 3 years, 3 months ago- ★★
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Tanabe Air compressor, When MAC started, Smoke came out of the crankcasee indicating Blowpass.
initial troubleshootings
1) piston ring brokenChanged all the piston rings and inspection of liner. All okay.
& it turns out there is a broken oring on the piston pin on tanabe MAC, which not everyone knew of or change during major overhaul.
All refrigeration system works like this
Compressor( High pressure, Hot gas refrigerant) > Condenser ( High pressure, Cooled liquid refrigerant) > Drier > Thermo expansion valve ( Low pressure, Cold liquid refrigerant) > Evaporator (Heat exchange takes place here, Low pressure, Hot Gas/Liquid refrigerant) > Compressor
Common problems i can think of.
1) Knocking of compressor indicates that liquid are returning to compressor. ( Clean the evaporator or condenser SW/FW side dirty, (Expansion valve settings)
2) Low suction pressure of compresser ( Refrigerent Top up )
3) Icing of evaporator (Ice room opened for too long causing higher humidity )
4) Low delivery pressure compressor valves leakage etc )
5) High delivery pressure ( Condenser dirty, not enough SW/FW)someone continue on the list !
One of the PSC / Class checks is checking if the reverse power reley is working.
How to check is… to run 2 generator on synchronise.
Changed the switch to manual, reduce the governer on the switchboard to reduce the load until negative. The generator should trip.
Understood from the above that Evaporated seawater meaning our distilled water generated from fresh water generator.
Ive only know of 2 chemical suppliers, DREW MARINE & UNITOR
For Unitor, jacket water treatment are using Natfleet to increase Nitrate levels. Nitrate levels are best kept above 1200.
If found faulty, some may want to replaced as a whole provided there is a spare.
If not if taking out for cleaning for routine maintenance, cleaning the piston(25), check the condition of the gasket on the valve disk(10).
Make a marking on the body before dismantling, as the center body consists of 2 different holes passage, 1 from inlet to the pilot valve and, 2nd from outlet to the diaphragm.Isolating valves
In the case of leakage area as shown above, Low low level alarm will be activated when the level of hydraulic oil decreases in the tank. When the alarm is activated, Both isolating valve will be activated & No.1 Lo pump will be switched over to No.2 pump.
4 Rams system work in a Pair. Thus when #4 Ram pipe is leaking, #3 & #4 ram is then isolated.
Through Lo #2 pump and only using #1 & #2 Ram, the system is still operable as shown above.
Unloader
From the above Unloader, the left box is when the steering is in operation and the right is for unloading.
The left box consist of 2 check valves, when in operation, the left check valve opens and prevents the return of the oil, and the right check valve for the returned oil is opened by the left line, thus allowing the oil return.
Relief valves
Relief valve reliefs the excess hydraulic pressure that might be created from waves acting on the rudder.
Operations of 4 Ram Steering gear
1)Steering gear pump is uni directional. During idle mode, there are no pumping stroke.
2)When torque motor sense signal from bridge, the directional control valve will operate to the direction by bridge and pump will be put to stroke.
3)After 10-20sec of starting, the unloading device will activate and pilot oil pressure will operate the unloading valve.
4)Pressurize oil from main pump go through rams thought isolating valve and turn the rudder
5)When desired angle is achieved, the potential meter give signal to bridge and bridge gives signal to torque meter to neutral position. Pump return to 0 stroke and run idle.4 Ram steering gear explaination Its a different diagram but similar concept.
Performance
1) Taken once a month, to check all is well, Pmax and Pcom is normal range, no abnormalities.
2) Normally i would take performance when changing over main running generator. For example this week AE #1 and im changing over to AE#2, i will take both performance at ~85% load. Depend on your company requirement.
3) Next week, when i’m changing from Ae#2 to Ae#3, i will take performance for AE#3. so by month end i will have taken all 3 AE.
4) Normally my practice is change Running AE estimate every 7days~ at sea. its fine to run more but its good to balance the running hours depending on yours.
5) During performance at high load, Check all your Fuel racks are almost equal, and Pcom and pmax are satisfactory.
6) If high deviation or exhaust temperature is high at high load provided at Pmax is okay, and dev more than 30-40degreeC, adjust the fuel racks a little turn and observe.
7)in my opinion, as long your pmax and pcomp is normal and fuel rack is almost equal at low load there tend to have some deviation and that does not matter. ( unit further away from the t/c scav space tend to have higher temp )Routine job for 3e
Tappet clearances
1) 2 rounds of your Flywheel is complete cycle of your 4- stroke generator, so for you to finish your tappet you just need to turn 2 rounds. Each round 3 units to adjust.
2) flywheel got 3 locations and marking; 1/6, 2/5, 3/4. 1st round of turning flywheel ( adjust the unit which both exhaust and suction valve are closed; check by making sure the push rod is free, if not just take out the cam cover and see the cam )
3) firing sequence for example 1-5-3-6-2-4, so go by that order. after adjust unit 1, go to 5, then go to 3. ( just take note sometimes the one turning the flywheel will overshot and give you the wrong flywheel position )
4) go by the feeler gauge. Dont go too tight or too loose, just dont be a perfectionist.. Lock nut dont be too tight either because the thread is easily spoilt. just spanner tight and tight by angle for ~40 degree. Very often the lock nut is damaged, if cant remove, my way is to just replace that particular rocker arm, because its not easy to remove the lock nut.
5) You can use your paint marker to mark on the nut and arm when done adjusting. So you can observe any movement next time you check visually.Crankshaft deflection
not only take reading, but know how to plot to know where is fault.
https://www.youtube.com/watch?v=QD3czPtlBf4
Fuel timing / cam timing
1) Turn the flywheel until the marking on the fuel pump meets the line. ( check manual ) that is the start of the injection,
2) Check the flywheel and note the angle. Fuel injection can be adjusted via adding shims or by adjusting the bolt depending on your generator type.
3) Do so for all units
4) Only adjust if there is fault on the injection timing( too early or late base on your performance chart) else dont touch it.Just sharing from my exp, we’re open for discussion here.
When taking over,
1) Just know the essential valves for your generator. How many valves to top up your sump oil. How much consumption of Lub oil per month. Normally 100 – 300 for 3 generator depend on running hour.
2) How many valves to close when overhauling. Mainly where the FO valves, cooling water valves to close and where to drain, starting air valve.
3) The previous 3e routine, if he had turbo-wash turbocharger gas or turbine side etc. Lub oil & fuel oil filter how frequent changed depending on the oil condition.
3) Check running hours to know around when is the next Top and major overhaul. If average running hour is 300h, how more months to next major. Need to order early.
4) take the first few days to check if you have all the spares required for overhaul, and critical spares.Impt Spares to look out for. Check your Manuel to know exact.
Generator attached pump
1)cooling water pump mechanical seals, oil seal & bearing.
2)lub oil pump spare gear, oil seal.
3)fuel oil attached pump mech seal or oil seal.For Top & major overhaul
For cylinder head;
Valve rotator, often neglected (steel ball, valve spring, spring plates )
Valve guides
Stem seals ( easily damaged when fitting, use proper tools if have or use a old stem seal as a cushion)
Suction & exhaust valves
exhaust & suction valve oring and seating ( rarely need to replace but good to have )
nozzle guide & oring ( rare but experienced leakage from here before )
Orings – for cooling water jacket, for oil return.
Gaskets – for your exhaust/ suction manifold, cylinder head metal gasket,
Piston rings – sufficient for how many times oh?Banjo plugs &spare copper gaskets < for cooling water fittings. From experience,dont need tight too much. if leaking then tight, normally solution is just replace copper gasket.
Fuel pump & injectors – keep spare & ready. Spares new barrel & plunger. when overhauling fuel pump check if barrel & plunger wear ( by covering the holes and feel the vaccum) When replacing injectors ( Test the nozzle before dismantling, so to determine to use back the nozzle or not, Check for leakage, spray and atomisation)
Turbocharger – if you have a new set. Check if got service kits for oh + spare bearings.
It good to make a point to put on your running hour sheet which Unit fuel pump you renewed new barrel and plunger, or new injector nozzle for future reference. Also remember to fill up your Nox Technical file for any job done on your AE.
Yeah totally. however i think whats most important is we should make sure this website is stable before opening the gates.From what I see that this website is secured from the padlock and https so no worry no information leak/ hackers.
