Efficient Operation Tips – Emergency Generator

1. Anti-freezing compounds are added to the emergency generators to ensure they will start even at very low temperatures (-ve temperature). If using a fully formulated anti-freeze compound, mix it with good-quality water in a ratio of 1:1 or as stated by the manufacturer. If the fully formulated antifreeze compound concentration is kept higher than required, the cooling system may silica gel formation issue.


2. When mixing anti-freeze solution into the system, avoid pouring it alone into the radiator. It should always be mixed in the prescribed ratio with water before pouring into the cooling water system of the generator.


This is because the potential of the ant-freeze liquid to remove heat is not as good as that of water and putting the anti-freeze compound alone in the cooling system may contribute to overheated conditions before the liquids are completely mixed together.


3. Coolant is used in the engine cooling water system to control the overheating of the generator. They are added mixing with water. Never add a coolant mixture at a low temperature to a hot engine. This may lead to damage to the engine casting. Always stop the engine and let it cool down before adding the coolant mixture.


4. When adding the coolant mixture after a major overhaul or draining the cooling system, ensure to open the engine and aftercooler vent while filling the coolant to the system to allow air to escape and avoid airlock


5. It is not a good practice to test the cooling water used in the emergency generator after a long interval of time. Ensure test the cooling water quality every week and maintain it at a pH of 8 – 10.5 to avoid excessive scaling problems (if calcium and magnesium levels are more) or corrosion problems (if chloride and sulphate levels are more)


6. Unlike the auxiliary engine generators, the emergency generator should not be idled for a long period. Long idle timing (more than 10 minutes) will affect the fuel burning as the combustion chamber temperature is very low. This will cause carbon clogging of the injector holes and sticking of the valve. The best idle time is considered to be 3-5 minutes for the emergency generator.


7. If the engine is idled for a long and the coolant temperature becomes too low (50-60 deg C), the fuel in the combustion chamber will remain unburnt and will wash the lubrication between the piston and liner, causing damage to the moving parts.


8. The most common problem found in the belts used in the engine to drive the water pump is cracks. Transverse cracks (cracks generated across the belt width) on the surface of the belt are acceptable within the prescribed limit. When the transverse crack is seen intersecting with longitudinal cracks, it is advisable to immediately change the belts.


Belt Cracks


9. The most common problem found in the radiator fan is the loosening of the screw, which connects the blades to the rotor. Never stand in front of the fan (which is set up outside the emergency generated room, to open the atmosphere) as a loose screw or broken blade may lead to a personal injury.


Never try to rotate the engine using fan blades to avoid injury or breakage of the blades themselves. Always stop and isolate the engine before tightening the screw on the blade or doing any other maintenance on the fan.


10. It is always advisable to fill the lube oil filter with lube oil (or fuel filter with fuel oil) before fitting the same to the emergency generator to avoid a dry start-up.


11. If an emergency generator is provided with a compressed air start system, ensure the compressed air unit does not have any lube oil carryover. Prolong carriage of lube oil will form varnish and carbon deposits around the piston of the compressed air chamber and it will not allow it to seal and generate the high pressure required for the starting.


12. After a major overhaul, it is important to vent the air trapped in the high-pressure fuel line (of injectors). Each high-pressure fuel line is to be vented separately by slightly opening the vent screw provided in the fuel line and by cranking the engine. If the engine needs to be started, ensure not to engage the starter for more than 30 seconds and provide a rest interval of 2 minutes before venting the next injector.


13. Avoid running with an oil mixture atmosphere to prevent overspeeding of the generator or explosion of the internal parts. Such an atmosphere is possible while loading hazardous cargo on the ship which can go inside the emergency generator through its air intake. Never mix gasoline or alcohol as it can cause an explosion.


14. After a major overhauling of the engine or when the Top Dead Centre (TDC) of the unit has to be marked, a locating pin is provided in most of the emergency generators which will sit in the hole of the gear drive attached to the camshaft, ensuring the first unit is in TDC. Once the TDC is located, ensure to remove the pin, else starting the generator will damage the pin and the locating hole


TDC Locating Pin


15. When the ship is plying in a low-temperature region for a longer duration, there is no provision to keep the emergency generator warm when it is not operational. It is advisable to use synthetic lubricating oil with low-temperature properties with a low sulphated ash limit .


The make and capacity of the emergency generator vary on ships and the engineer must know the operational and maintenance procedure of the machine thoroughly. The above tips broadly remain the same for all emergency generator models fitted on commercial ships and in case of doubt or assistance, it is always advisable to contact the makers for recommendations.  

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