Emergency Generator like any other normal generator on ship is required for the purpose of production of power (Electricity). But as name suggests, it is to be used in case of the emergency like Black Outs, getting ship to live after dead condition. Since the entire generator on a ship lies in the engine room, there has to be a source of supply that is outside this machinery space. Reason, well engine room is highly prone to fires and other factors, and thus there is a need of generator which is outside this space.
Otherwise:
- It is a small separate generator which supplies the electric power for emergency load in the event of main power supply failure.
- It is located outside the main and auxiliary machinery space and not forward of the collusion bulkhead.
- It has own switchboard near vicinity.
- It is provided with independent means of automatically starting (by air or battery) to ensure immediate run up following a main power failure and repeated starts of at least 3 times, and further attempt can be made within the 30 minutes.
- Adequate and independent supply of fuel with a flash point of not less than 43 °C
- Must be able to be started in cold condition up to zero (0 °C)
- For cold weather, JCW system must be treated with anti-freeze agent, and heating arrangement provided.
Rules and Regulations for Emergency Power Sources
- Emergency generator shall be automatically started and connected within 45 sec
- Emergency power source, Emergency generator must be sufficient to operate certain essential services at least for the period of 18 hours .
1) Emergency lightening (at alley way, stairways and exits, muster and embarkation stations, machinery space, control room, main and emergency switchboard, firemen’s outfits storage positions, steering gear room)2) Fire detecting and alarming system
3) Internal communication equipment
4) Daylight signaling lamp and ship’s whistle
5) Navigation equipment
6) Navigation lights
7) Radio installations, (VHF, MF, MF/HF)
8) One of the fire pumps, emergency bilge pump
Procedure for starting emergency generator when black out occurs ?
- Normally emergency generator cut in automatically when main power fails
- Starting is initiated by start up relay
- Falling of frequency or voltage of Main power, cause the start up relay to operate generator starting equipment
- If this system fails, after switching the MODE selector to Manual (Local) position, generator can be started manually by means of Back up starting equipment within 30 minutes of transitional emergency power battery lighting.
Maintenance:
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, oil level is checked on regularly basis. The condition of the oil will be known during this period and if the oil is having carbon or soot particles, change of complete oil system needs to be done. The running hours for changing of engine oil depends on the manufacturer, the engine make and the oil grade in use. Normally it is done between 250-500 hrs.
2. Clean Air Cleaner: The combustion air for the engine is passed through an air filter, which can be of following types:
1. oil bath air cleaner
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 dry cartridge, ensure to replace them at intervals stated by the maker. Normal replacement schedule is one year or after 5-7 cleanings.
3. Check Water Separator: Some emergency generators are provided with water separator to prevent 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 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. Generator with V-belts have additional alarm which will be sounded in the event of belt failure and operated by idler pulley.
6. Check V belt Tension: When V belt is fitted, inspect the same for cracks and damages. Renew the belt if damage/ cracking appearance is more. To check the belt tension, press the belt by thumb in 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 by pass filter, centrifuge filter, lube oil filter, fuel feed pump filter etc. These filters need to be cleaned or renewal of 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. Followed a proper planned maintenance system along with thorough regular checks is the key to ensure smooth running of emergency generators on board ships.
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