Why Ship Generators Shut Down Immediately?

10 Situations In Which Ship Generators Should Be Shut Down Immediately

As the main engine of a ship, ship generators require regular maintenance and overhaul to ensure their efficient and safe operation. A responsible engine engineer will not wait until the machine is on the verge of failure before performing maintenance. Instead, he will take all necessary precautions to protect the ship from any emergency problems that may arise from engine room failure or damage.

There is a fine line between the occurrence of a problem and its escalation. Only a ship engineer can assess the situation. However, every year, there are cases where auxiliary engines still fail after multiple indicators are detected, which foreshadow the occurrence of disasters.

The following ten situations require that the standby engine be started immediately and the auxiliary engine be shut down when any problem occurs, so as to avoid the situation escalating into a major disaster:

1. Abnormal/strange noise:

Ship generators are composed of heavy, vibrating, and moving parts. The auxiliary equipment connected to them, such as turbochargers and pumps, is also high-speed running machines that generate a lot of noise. Any abnormal sound, no matter how weak, should not be ignored. If an abnormal sound is detected, the engine must be stopped immediately , and the fault must be repaired.

Wrong way: The engine room is equipped with hundreds of mechanical systems. When the power plant is running, the sound of other machines may mask the abnormal sound. Even if you hear an abnormal sound from the generator, you may think it comes from the environment or nearby machines. Never ignore even the slightest abnormal sound. Consult other doctors and stop the engine for necessary inspections. Related reading: Comprehensive guide to engine room machine operating procedures

2. Smoke:

When you see smoke coming from or near the generator, stop the generator immediately. There is no need to empty the generator; the situation has exceeded the danger level. Please use the emergency stop button provided by the local or remote station. Smoke can be caused by friction between moving parts, overheating, or other factors.

Wrong approach: The first reaction of people when they see smoke or fire is panic. This will weaken the engineer's ability to think and ultimately slow down the approach.

There is no need to panic in this situation. Use the remote start button of the backup generator, which can start almost immediately (usually through the local station) and shut down the running generator in an emergency.

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3. Lubricating Oil Misalignment:

If the lubricating oil temperature is higher than normal or the oil pressure is lower than the proper level, shut down the generator immediately and find out the problem; it could be a dirty lubricating oil cooler or a clogged filter.

Wrong Way: If you notice a drop in pressure, the first thing that comes to mind is to replace the filter with a spare filter. If the spare filter is not ready for operation, air lock can cause serious bearing damage. It is best to shut down the machine first and then replace the spare filter after it is ready.

4. Increased Differential Pressure:

Differential pressure is used to evaluate the condition of the lubricating oil filter by measuring the pressure before and after the filter. The difference in filter pressure before and after operation is displayed by a pressure gauge. If the differential pressure is in the high range, stop the generator and replace the spare filter.

Wrong Way: We have observed that the generator often continues to run even when the differential pressure alarm is triggered during operation. Engineers are usually reluctant to risk changing filters while they are in operation, as it could cause a power outage if the filter is not functioning properly.

Therefore, they plan to change the filter after the operation is over. However, the differential pressure sometimes rises and the oil pressure suddenly drops, causing the generator to stop during operation. When the filter is opened for cleaning, it is likely to be found to be full of metal particles. This indicates that engineers are typically aware of the issue with the filter, but do not fully comprehend the scope of the problem.

5. Overspeed:

Generators are high-speed machines, and excessive engine speed has caused explosions and accidents in the past. Generator overspeed is primarily caused by fuel system issues, particularly governor failure. Suppose the generator is running at a speed exceeding the rated speed and not stalling (click here to learn about overspeed stalling). In that case, the technician must stop the machine immediately to avoid serious accidents. The crankcase must be checked, and the lower end bolts must be replaced.

Incorrect method: During the trial run after the generator is repaired, the governor elbow should be adjusted to achieve the required speed, as instructed in the manual. During this period, the generator may stall due to improper adjustment or fuel rail blockage. Failure to check the crankcase or replace the lower end bolts is a common cause of bearing damage.

6: Cooling water supply:

A cooling water supply is essential for the normal operation of all high-temperature moving parts. If the cooling water supply is interrupted due to pump failure, the machine must be shut down immediately to avoid overheating damage.

Wrong method: If the cooling water pressure in the pipeline is cut off, engineers sometimes try to bleed the fuel valve located near the generator expansion tank pipeline. Suppose the water supply is interrupted due to a pump failure. In that case, the temperature will further increase, eventually causing the generator to shut down, which can cause the moving parts to become stuck. Therefore, the generator should be shut down before checking for faults.

Once the generator shuts down due to a lack of water, the flywheel must be lubricated to prevent the parts from getting stuck.

7: Pipeline Leakage:

If any leakage is found in the fuel, lubricating oil or cooling water pipeline, it should be repaired after shutting down the generator. This way, engineers can easily repair the leak and perform maintenance better.

Wrong method: If a small amount of fuel or water leaks from any pipe connection, tightening the connection may stop the leak; however, over-tightening may cause a sudden increase in the amount of leakage. The splash of high-temperature fuel and water may cause severe burns to the operator's skin.

8. Vibration and loose parts:

Vibration is one of the main causes of wear of moving parts. If loose bolts or excessive vibrations are detected during engine operation, shut down the generator immediately and find out the cause.

Wrong method: On ships, it is not common to check the tightness of the generator anchor bolts and their accessories (such as turbochargers). It has been observed that many shipping companies ’ fleet management systems (PMS) do not regularly check the tightness of anchor bolts or other bolts.

9. Alarms and Trips:

If a generator alarm is detected to be faulty, it must be shut down immediately because other important alarms and trips may also fail. This can result in severe damage in the event of an accident.

Improper Operation: Many crew members tend to ignore alarms that they consider insignificant. Port State Control (PSC) frequently monitors alarms and trips from generators that are not functioning properly or are misconfigured. These situations are not conducive to preventing disasters. Please check all alarms and trips on a weekly basis.

10. Water in the Oil:

Water seeping into the oil reduces the oil’s load-carrying capacity and causes bearing damage. In this case, the generator should be shut down if the water content is too high. Locate the leak immediately and replenish or purify the crankcase oil before restarting the generator.

Improper Methods: Several cases have been reported where the generator lubricating oil was not checked regularly and the generator was allowed to operate with water in the oil. Even small amounts of water may not have an immediate effect, but over time, they can cause wear and damage to critical components in the crankshaft and bearings.

Ship Generator shutdown is not limited to the cases mentioned above. Other reasons may cause the generator to shut down immediately. However, it is the engineer's responsibility to utilize their experience and knowledge to prevent any type of failure in advance.