Diesel Generator Break-in Steps and Technical Requirements

Before a diesel generator set is officially put into service, it must go through a systematic break-in process. The main purpose of this break-in is to ensure that all components of the generator set adapt to operating conditions, reduce friction and wear during the initial operation, and maximize efficiency and lifespan. The quality of the break-in process directly impacts the stability and performance of the diesel generator set in the long term. This article outlines the steps, standards, and technical requirements after the break-in process.

No-load Running Break-in

The no-load running break-in is the first step of the process, aimed at conducting an initial check with low load operation to ensure the coordination and proper functioning of all components. The steps are as follows.

1. Inspection and Preparation

Before starting the generator set, check key components such as engine oil, coolant, fuel, and battery levels to ensure they meet technical requirements. Special attention should be paid to the oil and coolant levels and quality, ensuring they meet operating standards.

2. Start-up and High-Speed Operation

After starting the generator, adjust the engine speed to high idle and maintain it for 10 minutes. During this period, operators should monitor oil pressure, engine sounds, and exhaust conditions to ensure no abnormal performance.

3. Shutdown and Temperature Check

After 10 minutes of running, shut down the generator and check the temperature of key components like the main bearing and connecting rod bearings by touch. Ensure that temperatures do not exceed 80°C, meaning the components should not be too hot to touch. If the temperature is normal and there is no unusual noise or vibration, the no-load running break-in is complete and the next step can begin.

4. Additional Checks

After shutdown, recheck the condition of all components, especially the lubrication and cooling systems, ensuring there are no leaks, vibrations, or other potential issues.

Gradual Increase in Speed

Once the no-load running break-in is successful, the next step is to gradually increase the generator set's speed, allowing the engine to adapt to higher operating intensities and preparing for the thermal break-in.

1. Gradual Speed Increase

During this phase, the engine speed should be gradually increased from low speed to rated speed. Each increase should be by 2000 rpm, maintaining stable operation at each speed for at least 2 minutes. The increase should be smooth and should not exceed the maximum no-load speed set, typically 5-10 minutes below the rated speed.

2. Temperature Control and Monitoring

Throughout the speed increase, the coolant temperature should be maintained between 75-80°C, and the engine oil temperature should not exceed 90°C. High temperatures may lead to poor lubrication and increased wear on components, so the cooling system must be carefully monitored.

3. Sound and Vibration Check

During operation, carefully listen for any abnormal noises, as they may indicate problems such as gear wear or bearing damage.

Load Break-in

The load break-in is a crucial step in the process. By gradually increasing the load, it allows the components to operate stably under various load conditions, preparing the generator set for full-load operation.

1. Gradual Load Increase

Begin the load break-in with a low load and gradually increase it until reaching 80% of the rated load. The load increase should follow this order:
Start with 25% of the rated load.
Increase to 50% of the rated load.
Finally, reach 80% of the rated load.
For each load increase, ensure the generator runs for a sufficient time at each load, confirming stable operation without any issues.

2. Oil Check and Change

During the load break-in, check the oil level every 4 hours and add oil if necessary. When changing the oil, clean the oil sump and oil filter to ensure the lubrication system remains clean and operates normally.

3. Bolt Tightening Check

Regularly check the tightness of key bolts, such as those on the main bearing, connecting rod, cylinder head, fuel pump, and injectors. If any bolts are found to be loose, tighten them promptly to ensure the generator operates stably.

4. Valve Clearance Adjustment

Valve clearance may change during the break-in, so it should be checked and adjusted as necessary. Proper clearance ensures the engine valves open and close correctly, improving engine efficiency and longevity.

Hot and Cold Break-in

The diesel generator set's break-in typically includes both hot and cold phases. Each phase has different methods and durations, but the goal is the same: to allow internal components to gradually adapt to operating conditions and minimize initial wear.

1. Hot Break-in

During hot break-in, the generator should run without load, typically at speeds below 1300 rpm. After running without load for a specified time, the generator can begin the load-bearing phase of the hot break-in. The process should last around 60 hours, with the load gradually increasing until it reaches the rated load.

2. Cold Break-in

Cold break-in is achieved by using external forces (such as a battery or manual turning of the flywheel) to operate the engine without starting it. This helps to remove impurities inside the system and ensure the lubrication system is not contaminated. After cold break-in, the oil in the sump should be drained and the system cleaned with flushing oil to ensure clear oil passages.

Technical Requirements After Break-in

Following a thorough break-in, the generator set should meet the following technical requirements to ensure stable and efficient operation when put into service.

1. Starting Performance

The generator set should start quickly and reliably under any conditions, with the engine speed stabilizing smoothly after start-up, without abnormal fluctuations.

2. Operating Stability

The generator should maintain stable operation within the rated load range, without overloads, overheating, or uneven speeds. It should be able to quickly stabilize speed when there are sudden changes in load.

3. Load Transition and Exhaust Conditions

When transitioning from one load condition to another, the load should change smoothly without jumps. The exhaust should be normal, without excessive black or white smoke.

4. Leakage-Free Operation

After break-in, ensure that there are no oil, water, air, or electrical leaks. These potential issues must be fully addressed to ensure safe and efficient operation.

Conclusion

By following a carefully planned break-in process, the diesel generator set can minimize initial failure risks, enhance the coordination and stability of its components, and lay a solid foundation for efficient long-term operation. The break-in phase not only serves as a "tuning" process for the components but is also a key step in ensuring the generator set operates reliably and efficiently for years to come, supporting stable power supply.