Following are some important maintenance jobs that need to be carried out in emergency generators on ships:
1. Change of Engine Sump Oil:
It is important to check the oil level in the sump regularly. Since the emergency generator is kept on auto mode, which ensures the generator starts and comes on load automatically, it is necessary that before starting the engine for operation, the oil level is checked on a regular basis.
The condition of the oil will be known during this period and if the oil is having carbon or soot particles, a change in the complete oil system needs to be done. The running hours for changing of engine oil depend on the manufacturer, the engine makes and the oil grade in use. Normally it is done between 250-500 hrs. The oil changing period must be cut by half when the fuel used in the generator is more than 0.5% to 1% sulfur.
2. Clean Air Cleaner:
The combustion air for the engine is passed through an air filter, which can be of the following types: 1. oil bath air cleaner and 2. dry type air cleaner (cartridge or dust collector). It is important to clean the air filter at correct intervals of time as delay will lead to clogging and less air going in the engine. This will reduce the efficiency of the engine and increase the thermal parameters.
When using a dry cartridge, ensure to replace them at intervals stated by the maker. The normal replacement schedule is one year or after 5-7 cleanings.
3. Check the Water Separator:
Some emergency generators are provided with a water separator to prevent the mixing of water with fuel. Check the level of water and make sure it is below the marked level and regularly drained off.
This is to be done to avoid rust and corrosion of fuel line devices and to avoid incomplete combustion.
4. Check the Electrolyte in the Battery:
A battery is used in one of the starting methods of the emergency generator. The electrolyte level in the battery must be checked at regular intervals either by inserting a level stick or by checking the water level in the level tester cap (if provided). Use distilled water to make up for the low level.
5. Check Alarms and Shutdowns:
All the safety devices and alarms fitted in the emergency generator must be checked and tested regularly. Generators with V-belts have an additional alarm that will be sounded in the event of belt failure and operated by an idler pulley.
6. Check V belt Tension:
When the V belt is fitted, inspect the same for cracks and damages. Renew the belt if the damage/ cracking appearance is more. To check the belt tension, press the belt by the thumb in the midway of the pulleys and check the inward deflection in mm. It should not be more than 10-15 mm depending upon the make of the generator.
7. Clean Oil Filter Cartridge:
The emergency generator is provided with various oil filters such as bypass filter, centrifuge filter, lube oil filter, fuel feed pump filter, etc. These filters need to be cleaned or renewal of the filter cartridge is to be carried out as per the maker’s instruction or oil condition.
8. Check Valve Clearance:
The tappet clearance of the inlet and exhaust valve should be checked at running hours stated in the maintenance section of the generator’s manual. Also, ensure the engine is cold before taking the tappet clearance.
Loss of emergency generators at times when they are needed the most can lead to unfortunate and disastrous incidents. Following a properly planned maintenance system along with thorough regular checks is the key to ensuring the smooth running of emergency generators on board ships.