Diesel Generator Startup, Operation, and Shutdown Procedures
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Before starting a diesel generator, a series of necessary checks and preparations must be made to ensure the reliability and safety of the equipment. The startup process, along with environmental conditions, can significantly affect the performance of diesel generators, especially in varying temperatures. This article will outline the pre-startup inspection steps, startup procedures for normal and low temperatures, key points after starting, and the correct shutdown process.
Pre-Startup Inspection and Preparation
Before starting the diesel generator, it is crucial to ensure all preparations are in place. Here are the key checks that need to be performed before starting.
1. Inspecting Components
First, check if all parts of the diesel generator are in normal condition. Ensure there are no signs of wear, looseness, or damage. All connections should be firm and secure to avoid any issues during operation.
2. Adding Coolant and Fuel
When adding coolant, if using an open-loop cooling system, make sure the water level is above the generator's freshwater pump. Fill the engine oil to the required level and add sufficient fuel to meet the startup and running needs.
3. Checking the Electrical System
Ensure the wiring in the electrical system is correct, and check if the battery is fully charged. The electrical system is a critical part of starting the diesel generator, and any faults in the circuitry could result in startup failure or equipment damage.
4. Removing Air from the Fuel System
Open the valves on the fuel tank and use the manual pump on the fuel supply system to remove any air. Loosen the bleed screw on the injection pump and manually operate the pump until the fuel flows out without air bubbles, ensuring smooth fuel supply.
Startup Procedure in Normal Temperature
When the ambient temperature is above 5°C, starting the diesel generator is relatively straightforward. Here are the steps.
1. Adjusting Fuel Supply
Move the fuel control lever on the injection pump to the idle position, with the speed set to around 700 RPM. This adjustment provides the right amount of fuel to ensure a smooth startup.
2. Starting the Electrical System
Turn the key (for 12-cylinder units, turn it to the “right” position) and press the start button. If the generator does not start within 5 to 10 seconds, release the button and wait for 1 minute before attempting again. If it fails to start after three attempts, stop and investigate the issue before trying again.
3. Operations After Starting
Once the generator starts, release the start button and turn the key back to the neutral position (for 12-cylinder units, turn it to the “left”). Monitor the instrument readings, especially the oil pressure gauge, which should read above 0.5 kg/cm² (at 500 RPM). Let the generator run at 600 to 750 RPM for a while to check the operation of all parts, such as the valve mechanism and lubrication system.
Low-Temperature Startup Procedure
Starting a diesel generator in low temperatures is more challenging, especially for naturally aspirated and turbocharged units. The steps are as follows.
1. Naturally Aspirated Generators
When the ambient temperature is below 0°C, heat the engine oil to around 40°C and pour it into the oil sump. Heat the coolant to above 80°C. After these preparations, follow the normal startup procedure.
2. Turbocharged Generators
For turbocharged generators, the startup procedure is more demanding due to the higher compression ratio. Use the pre-heater on the intake pipe, heat the fuel, and set the fuel control lever to idle at around 700 RPM. Press the preheat button for 15 minutes, then press the start button. Additional measures such as heating the oil and coolant may also be required. In extremely cold regions, using low-temperature batteries and special oils and fuels helps ensure successful startup.
Operation and Load Control After Startup
After the diesel generator starts, let it run without a load, gradually increasing the speed to 1000 to 1200 RPM. Then, move to partial load operation. When the coolant temperature exceeds 55°C and the oil temperature exceeds 45°C, you can switch to full load operation.
1. Controlling Load and Speed
Increase the load and speed gradually to avoid sudden changes, which can cause stress damage to the generator. For new generators, it is recommended to run at no more than 80% of the rated load for about 60 hours to ensure proper break-in of the moving parts and improve reliability.
2. Post-Overhaul Inspection
For generators that have undergone major overhauls, check the working condition of the moving parts within the first half hour after startup to ensure all components are functioning properly.
Shutdown Procedure
When shutting down the diesel generator, follow the standard procedure to ensure safe and proper operation.
1. Gradual Load Reduction
Before shutting down, gradually remove the load and reduce the speed to 700 to 1000 RPM by adjusting the fuel control lever to the low-speed position. Let it run for a few minutes, then move the shutdown lever to stop the generator.
2. Electrical Key Operation
After shutdown, return the key to the neutral position to prevent reverse current flow from the battery, which could damage the electrical system.
3. Winter Anti-Freeze Measures
In winter or cold regions, drain the coolant from the generator after shutdown to prevent freezing and cracking of the engine block. If antifreeze is used, draining is unnecessary.
4. Emergency Shutdown
In an emergency, use the emergency stop lever to quickly shut down the generator and avoid severe accidents. Afterward, immediately inspect the generator and perform any necessary repairs.
Conclusion
Starting, running, and shutting down a diesel generator must be done following standard procedures, especially when environmental conditions vary. Proper inspection, preparation, and operational steps, along with careful load control and shutdown practices, can significantly enhance the lifespan and efficiency of the generator, ensuring reliable operation across various applications.
