1、 Problems in maintenance methods of generator sets
Because some maintenance personnel do not have a clear understanding of the mechanical structure of the generator set, do not carefully analyze the fault causes, and can not accurately judge the fault location, they adopt the "rough" idea to unload the generator set blindly, which not only does not eliminate the original fault, but also believes that the original error has not been eliminated. Due to poor maintenance technology and process, new problems have emerged. If the power of the 120 kW diesel generator is insufficient, the mechanical failure will not work. The maintenance personnel disassembled and disassembled the PT fuel injection pump and fuel injector, and found no fault cause. When replacing an injection pump, the fault still exists. The final inspection failure was caused by excessive impurities and moisture in the diesel used. However, this disassembly actually led to a significant decline in the performance of Pt injection pump and insufficient power of diesel generator. Therefore, after mechanical failure, the generator set is tested by test; If the generator set is not tested, determine the most possible fault location through "ask, look, look up" and other traditional fault diagnosis methods and means, combined with the structure and working principle of the generator set. When judging the fault of the generator set, the "troubleshooting method" and "comparison method" are usually used , avoid "ignoring red and white, blind disassembly and large-scale disassembly" according to the order from simple to complex, first appearance, then internal, first assembly and then parts.
2. The phenomenon of blindly replacing and repairing parts exists to varying degrees.
It is relatively difficult to judge and eliminate the faults of the generator set. Some maintenance personnel always use the method of replacing parts test, whether large or small. As long as they think that the fault may be caused by the parts, they will carry out the replacement test. As a result, not only the faults are not eliminated, but also the wrong replacement of spare parts increases the maintenance cost.
For the fault parts such as generator, air compressor, blower, burner and gear pump, their technical performance can be restored through repair without complex repair technology. During the maintenance process, the cause and position of the fault shall be carefully analyzed and judged according to the fault phenomenon, and repair methods shall be adopted to restore the technical performance of repairable parts and eliminate blind replacement of parts.
3. There are many phenomena that do not pay attention to the matching clearance of parts.
Common diesel generator maintenance and assembly clearance piston and cylinder liner piston ring, "three gaps" , tip clearance, valve clearance, plunger clearance, brake shoe, side clearance of master-slave gear, axial and radial clearance of bearing, guide fit clearance of valve stem and valve, etc. various models have strict requirements, and parts must be adjusted or replaced during maintenance and measuring the clearance that does not meet the requirements. In actual maintenance work, it is very common to blindly assemble parts without measuring the fit clearance Lead to early wear or ablation of bearings, oil combustion of diesel generators, difficulty in starting or deflagration, fracture of piston rings, impact of parts, oil leakage and air leakage. Age. Sometimes serious mechanical damage accidents will occur even due to improper matching clearance of parts.
4. When the generator is assembled, the counter is installed from time to time.
In some maintenance of generator sets, parts and components and the direction of strict requirements; only the correct installation can ensure normal operation. The external characteristics of some parts are not obvious, and both positive and negative can be installed. In practical work, reverse loading often occurs, resulting in early damage of parts, mechanical failure, generator set damage accidents, etc. engine cylinder gasket and unequal distance are installed Valve spring, engine piston, piston ring, fan blade, gear pump side plate, skeleton oil seal, thrust washer, thrust bearing, thrust gasket, oil baffle ring, fuel injection pump plunger, clutch friction disc hub, transmission shaft universal joint and other components. If you do not understand the structure and installation notice, it is easiest to install the counter. Abnormal operation occurs after assembly, resulting in generator set failure. Maintenance personnel are assembling parts. Therefore, they must understand the structure and installation direction of components, and do not take it for granted and install blindly.
5. The maintenance method is not standardized. Palliative treatment is still a habit of some maintenance units.
In the maintenance of generator set, some maintenance personnel do not take correct maintenance methods, and think that emergency measures are omnipotent, "emergency" rather than "maintenance", and there are still many phenomena of "palliative but not cure". For example, they often encounter "welding instead of repair" , is an example. Some of them can be repaired, but some of the maintenance personnel's plans are easy. In order to make the diesel generator increase the fuel supply quantity of the fuel injection pump and improve the fuel injection pressure of the fuel injector. These irregular maintenance methods can only be used in emergency situations, but can not be used for a long time. We must fundamentally find out the cause of the fault and take regular maintenance measures to eliminate it In addition to the fault, it has attracted the attention of maintenance personnel.
2、 Problems in maintenance materials and accessories of generator set
1. Failure after assembly is a common problem, and the quality of new parts is not checked.
It is unscientific for some maintenance personnel to install new parts directly on the generator set without technical inspection before replacing parts. At present, the quality of parts sold in the market is uneven, and some fake and shoddy parts are mixed. The performance of some parts changes due to long storage time. If there is no test, they often fail after assembly. Therefore, in Before replacing new accessories, necessary inspections and tests must be carried out. The tests include appearance and performance tests to ensure that the new accessories have no faults and avoid unnecessary trouble.
2. Do not pay attention to the model accessories, and the replacement or abuse of accessories is common.
The replacement or misuse of accessories is more common in the maintenance of generator sets. Emergency replacement of some parts is feasible, but long-term use is harmful and useless, which affects the safety and technical performance of generator sets. Some maintenance personnel have little understanding of the principle of mechanical structure, and many spare parts do not match, but they believe that as long as they can be installed on the line, they will not consider whether to play their role Technical performance of machinery: replace qualified products with defective products, replace cotter pins with iron wires and nails, and replace cylindrical pins with steel bars and IET bolts. The quality can not be guaranteed, and long-term use is not allowed. When maintaining the generator set, try to use original types of accessories, which can not replace parts with other types, let alone abuse, unpaired, and change components in a complete set See you a lot.
There are many generator set components such as plunger pair, outlet valve pair and injector needle valve assembly in the fuel system of diesel engine. These matching components are specially processed and ground in pairs in the factory manufacturing process. The matching is very precise Zhun, and they are always used in pairs for their service life and are not interchangeable. Some supporting components, such as piston, cylinder liner, bearing, journal, etc After use for a period of time, the matching is good. During maintenance, pay attention to assembly and do not string lines. If these machines use a set of accessories at the same time, if they are damaged, they must be replaced in a complete generator set. Otherwise, the generator set will be in an unstable state due to the huge difference in the quality of parts, the difference between old and new products, the difference in size and length, The replaced parts are easy to be damaged in the early stage. In the actual maintenance work, in order to reduce the cost, some people do not understand the technical requirements and the unmatched or completely replaced parts are not scarce, which reduces the maintenance quality of generator set, shortens the service life of parts and increases the possibility of failure, which should be paid enough attention.