The generator onboard, being the powerhouse of the ship, requires regular maintenance and overhauling to ensure efficient and safe operations. Listed below are ten cases wherein you must immediately start the standby engine and stop the auxiliary engine in “trouble” before a dangerous situation takes shape of a major disaster:

1. Abnormal/ Queer Sound: The ship’s generator engine comprises of heavy oscillating and moving parts. The attached auxiliaries such as turbochargers, pumps etc. are also high-speed machines which produce a good amount of sound. Any abnormal sound, no matter how faint, must never be ignored. In case of an unusual sound, the engine should be immediately stopped and troubleshooting must be carried out.

2. Smoke: When you see smoke coming from or near the generator, it’s high time to stop the generator immediately. No need to offload the generator as the situation has already passed the danger level. Use the emergency stop button provided in a local or remote station. Smoke can be due to friction between moving parts, overheating etc.

3. Unusual Lubricating Oil Parameters: If the lubricating oil temperature has increased beyond normal or the oil pressure has dropped below the adequate level, stop the generator immediately and find out the troubling issue, which might be a dirty lube oil cooler or chocked filter. If your standby filter is not primed and put in service in running condition, due to airlock major bearing damages can occur. It’s always better to stop the machinery and then change it to standby filter, only after priming the same.

4. Higher Differential Pressure: Differential pressure is a term used to assess the condition of lube oil filter by providing a pressure measurement before and after the filter. The difference between the before and after filter pressures is displayed by a gauge. If the differential pressure is in the higher range, stop the generator and change to standby filter.

On numerous occasions, it has been observed that the generator is allowed to run even when the differential pressure alarm is sounded during maneuvering. Engineers usually prefer not to take risk of changing the filter in running condition, as it may lead to blackout if the filter does not perform correctly. They thus plan to change it once the maneuvering is over.  However, due to this sometimes the differential pressure increases further and there is a sudden drop in oil pressure, which trips the generator in between maneuvering. It is very much possible to find bearing metal particles when filters are opened for cleaning. 

5. Overspeed: Generator is a high-speed machinery and over-speeding of generator engine has resulted in explosions and causality in the past. Over-speeding of the generator is caused mainly due to a problem in the fuel system, specifically malfunction of the governor. If the generator is running above its rated speed and still does not trip (Read about overspeed trips here), engineers must stop the generator immediately to avoid a major accident. Crankcase inspection and renewal of bottom end bolts is then to be carried out.

6. Cooling Water Supply: Cooling water supply is an essential entity to ensure a smooth running of all high temperature moving parts. If there is no cooling water supply due to the failure of pumps, the generator should be stopped immediately to avoid overheating damage.

7. Leakage from Pipings: If any leakage is found from the fuel, lube oil or cooling water pipe, it is to be rectified only after stopping the generator. This will allow the engineer to tackle the leakage easily and better maintenance can be carried out.

8. Vibration and Loose Parts: Vibration is one of the main causes which increase the wear rate of moving parts. If loose bolts are found or heavy vibration is detected when the engine is running, stop the generator engine immediately and find the cause for rectification.

9. Non-functional Alarms and Trips: During any point of time, if an alarm of the running generator is detected not to be working, then the generator needs to be stopped immediately as there is a possibility that other important alarms and trips are also not working. This can lead to major failure if an accident occurs in the generator.

10. Water in Oil: Water leaking in oil will decrease the load carrying capacity of the oil and leads to bearing damages. In such cases, the generator must be stopped if the water content is very high. Immediately find the leakage and renew/purify the sump oil before bringing the generator back in operation.

In addition to the above cases, there are many other reasons why we must stop the ship's generator immediately. Regularly observing and paying attention to any abnormal signs is an important factor in avoiding problems with the generators on board, helping the ship to operate efficiently and safely.

Source: Marine Insight