About Diesel Generator 2

Diesel generator is an independent power generation equipment, which mainly provides emergency power supply in case of power failure. In fact, the unit is in standby state for most of the time, and there are few opportunities to actually put it into use. It usually focuses on commissioning, and lacks perfect detection and maintenance means. However, this emergency standby power supply is indispensable. How to ensure that the generator can supply power in time in case of emergency when it is rarely used at ordinary times, operate safely and reliably, and shut down immediately after power failure.

First, check the battery pack.

Since the standby power supply is not often put into use, whether the generator can start normally depends on the maintenance of the battery. If there is a problem with the battery pack, the more common situation is whether there is voltage or current. At this time, you can hear the sound of the solenoid valve in the starting motor, but you can't move the coupling. There are three reasons why the battery pack cannot be shut down due to problems. 1. Stopping charging the battery during commissioning will lead to insufficient battery power.

2. The mechanical oil pump is driven by the belt. The pump oil at the rated speed is large, but the power supply of the battery pack is insufficient, resulting in shutdown. The spring plate in the shut-off valve cannot seal the fuel ejected from the four oil outlet holes due to insufficient suction of the solenoid valve.

3. Domestic batteries usually have a service life of two years and are not replaced regularly.

Second, check the starting solenoid valve.

When the generator is running, people have summed up a set of inspection methods of "one look, two listen, three touch and four smell". Listening at start-up is a very important step. Take the original Cumming generator in the United States as an example. It can be started only after pressing the start button for three seconds. Two "clicks" can be heard within three seconds. Once the second sound is not heard, check whether the starting solenoid valve works normally. If the solenoid coil burns out, of course, the generator cannot be started.

Third, inspection of diesel and lubricating oil.

Because the unit is static for a long time, various materials of the unit will undergo complex chemical and physical changes with engine oil, cooling water, diesel oil, air, etc., so as to "blow" the unit. Therefore, attention should be paid to the problem of oil. For fire safety, the diesel oil tank is usually placed in a closed room. Due to the condensation of water and gas in the atmosphere due to temperature changes, water droplets are formed and attached to the inner wall of the oil tank and flow into the diesel, resulting in the water content of the diesel exceeding the standard. Such diesel entering the diesel engine high-pressure oil pump will rust the precision coupling plunger and seriously damage the unit. The generator lubricating oil has a storage period. The physical and chemical properties of the lubricating oil stored for a long time will change, resulting in the deterioration of the lubrication state during the operation of the unit, which is easy to cause damage to the generator parts.

Principles and methods

The causes of diesel generator set faults are usually caused by various factors. Different faults show different phenomena. To eliminate the faults, we must first find out the causes of the faults. In practice, we can find the abnormal performance of diesel engine by looking, listening, touching and smelling, so as to find the problems, solve the problems and eliminate the faults. The general principle of judging diesel engine fault is to combine the structure, contact principle, clarify the phenomenon, combine the reality, from simple to complex, from the outside to the inside, according to the system section, and find the cause. In the long-term production practice, people have explored and summarized a set of inspection methods of "one look, two listen, three touch and four smell", and observed and judged the operation of diesel engine through instrument monitoring and the feeling of human organs.

The following phenomena are usually encountered when the diesel engine fails after long-term operation.

1. The sound is abnormal during operation. The diesel engine sends out abnormal knocking sound, blasting sound, booing sound, exhaust sound, periodic friction sound, etc.

2 abnormal operation, the diesel engine is difficult to start, severe vibration occurs during operation, unable to drag the load, unstable speed, etc.

3. The appearance is abnormal. The exhaust pipe of the diesel engine emits white smoke, black smoke and blue smoke, and each system has oil leakage, water leakage, air leakage, etc.

4. Abnormal temperature, excessive oil temperature or cooling water temperature, bearing overheating, etc.

5. Abnormal odor. The diesel engine emits odor, scorch, smoke and other odors during operation.

After the above abnormal phenomena are found during the operation of diesel generator set, careful investigation must be carried out to find out the location and cause of the fault according to the analysis and judgment of fault phenomena. Sometimes a fault may have several abnormal phenomena. For example, after the high-pressure oil pump is worn, it can not only show difficult start-up, insufficient output power, but also unstable low-speed operation. Sometimes an abnormal phenomenon may be caused by several faults. Therefore, we must carefully find out the causes of the abnormal phenomena when the diesel engine is running, which requires us to be good at analysis, reasoning and judgment, grasp the essence through the phenomena, find out the causes and parts of the faults, and eliminate the faults.

1. Judge the fault position according to the abnormal sound. Use a through-hole screwdriver or a fine iron bar sharpened at one end of half a meter long to "listen to the needle judgment". One end is close to the ear, and the other end touches the surface of each inspection part, so as to clearly monitor the size and nature of the part sound generated by the abnormal sound. Sounds from different parts are often different. For example, if the clearance of the main bearing is too large, the impact sound is dull, and the impact sound of the valve and piston is crisp. If the flywheel key way fits loosely, the impact sound will be sent out, etc. Therefore, the fault location will be judged according to different sounds.

2. local stop method is used to judge. After fault analysis, if it is suspected that the fault is caused by a cylinder, the cylinder can be stopped to observe whether the fault phenomenon disappears, so as to determine the cause and location of the fault. For example, the analysis of black smoke from diesel engine shows that the nozzle hole of a cylinder is blocked, and the oil supply to the cylinder can be stopped. If the black smoke disappears, the judgment is correct.

3. use the comparison method to judge. According to the fault analysis, it is suspected that the fault may be caused by a certain part or component. Replace the part or component with a new one, and then start up and run. Compare whether there are changes in the working conditions before and after the diesel engine, so as to find out the cause of the fault.

4. use the heuristic method to judge. According to the analysis of the cause of the fault, it is difficult to judge at the moment. You can change the technical state in the local range to observe whether the working performance of the diesel engine is affected, so as to judge the cause of the fault. For example, the diesel engine can not produce the specified power. It is suspected that the insufficient compression stroke pressure of a cylinder is caused by the large gap between the cylinder and the piston and the lax sealing. At this time, open the cylinder head, inject a small amount of oil into the cylinder to improve the sealing condition, and then re-install the cylinder head for start-up test. If the pressure increases and the output power increases, the analysis is correct.

After long-term use, diesel generator sets have many fault phenomena. Due to different models of diesel engines, domestic and imported ones have different structures and service environments, and the fault causes are also different. Therefore, when dealing with problems, specific problems should be divided according to different situations. Correctly analyzing and judging the cause of diesel engine fault is a detailed work. It is not allowed to disassemble the diesel engine before clarifying the cause of the fault. This will not only not eliminate the fault, but may not meet the technical requirements when reassembling the disassembled parts and components, resulting in new faults.