Technical Paper on Electrical Equipment Maintenance-Maintenance Principles and Analysis of Electrical Equipment
Abstract: With the rapid development of social market economy and the continuous improvement of people's living standards, electrical equipment is widely used in people's daily life, which brings great convenience to people's production and life. However, many electrical equipment will have various faults in the process of use, which requires good repair and maintenance of electrical equipment. Based on the maintenance principle of electrical equipment, this paper analyzes the inspection methods and effective maintenance of electrical equipment.
[Keywords:] electrical equipment; Maintenance principle; Maintenance; analyse
China Library Classification Number: TD327.3 Document Identification Number: A Document Number:1009-914x (2014) 20-016-01.
With the increasing number and types of electrical equipment in people's daily life, the maintenance of electrical equipment becomes more and more important. In the process of electrical equipment maintenance, maintenance personnel should first understand various maintenance principles of electrical equipment maintenance, so as to complete the maintenance of electrical equipment well. According to the maintenance principles of electrical equipment, this paper expounds the troubleshooting methods and maintenance methods of electrical equipment.
First, the fault inspection method of electrical equipment
The inspection methods of electrical equipment faults mainly include: short circuit method, forced closure method, step-by-step open circuit method, component replacement method, comparison method, intuitive method and so on. These methods will be explained in detail below.
Short-circuit method, the causes of circuit failure of electrical equipment are mechanical part failure, electrical electromagnetic failure, wiring error, grounding, open circuit, overload, short circuit and so on. Among these common faults, open circuit fault is the most common, and open circuit fault can be checked by voltage check method and resistance check method. Another simple and reliable method is short circuit method, because the circuit has an open circuit fault. The main causes of this fault are: virtual wire connection, open wire, loose wire link, blown fuse, false welding, virtual welding, poor contact, etc. The main operation method of short circuit method is to select wires with good insulation performance. If it is suspected that there is an open circuit in a certain part of the electrical equipment, it will be short-circuited with wires. If the circuit returns to normal after short circuit, it means that there is an open circuit fault in this section.
Forced closure method, if the fault point is not found by visual inspection when checking the fault of electrical equipment, and there is no suitable testing tool for measurement at the moment, this is to select insulating rods with good insulation to forcibly close related electromagnets, contactors, relays, etc. And then observe what changes have taken place in the corresponding mechanical or electrical parts. If the corresponding electrical part does not work normally, the fault location and fault type can be judged accordingly.
Step-by-step open circuit method, if the circuit structure is complex and there are circuits with multiple branches connected in parallel, when one of the circuits is grounded or short-circuited, no obvious changes can be seen by intuitive observation, and no abnormal phenomena such as sparks and smoke will occur. For example, when a circuit with a protective cover or a motor is short-circuited, no external phenomenon of other circuit faults can be seen except the fuse is blown. At this time, the most suitable fault inspection method is the step-by-step open circuit method. The main inspection method is to encounter complex circuits, and it is difficult to detect grounding or short circuit faults. At this time, the melt can be replaced first, and the parallel circuits of multiple branches can be disconnected one by one, and then the power-on test can be carried out. If the fuse blows again and again at this time, it means that the fault is in this newly disconnected circuit. In order to find the specific location of the fault, then check the circuit in sections, access the circuit in sections, and conduct the power-on test. If the fuse blows again when connecting a certain circuit, it means that the fault is caused on this circuit. This inspection method is very simple, but it has a disadvantage, that is, in the process of open circuit inspection and power-on, it is easy to completely burn the components that are not seriously damaged.
In the component replacement method, some circuit faults take a long time in the inspection process, and the fault location is not easy to determine. At this time, in order to ensure the working efficiency of electrical equipment, a group of identical components with good performance can be used to replace the faulty components. If the electrical equipment returns to normal after replacement, it means that the circuit fault occurred in this group of components. However, when replacing parts, be sure that the damage is caused by the failure of the parts themselves, so as to avoid the damage of parts again after replacing new parts.
Contrast method, when the circuit fails, detect the relevant parameters in the circuit. In order to find out the cause of the fault, the detected data can be compared with the normal parameter values recorded in drawings and peacetime, and the cause of the fault can be found by comparison. If the data during normal operation is not recorded, it can be compared with the parameter values of the same type of electrical equipment during normal operation.
Intuitive method, as its name implies, is to find out the abnormal parts of electrical equipment through external observation when the electrical equipment fails, so as to judge the fault parts and causes. When the end of the wire is loose, the contact of the electrical appliance is easy to generate sparks when closing the breaking circuit. When checking the circuit fault with an intuitive method, the fault condition of the circuit can be judged according to the existence and size of the spark generated by the circuit. For example, when a spark is found between a normally tightened screw and a wire, it means that the end of the wire is loose or the contact is poor in the circuit. In the circuit, there are sparks in two phases of the main contact of the contactor that controls the motor. When there is no spark in one phase, it means that the contact without spark in this phase has been disconnected or has poor contact. Three-phase sparks are larger than normal, indicating that the mechanical part is stuck or the motor is overloaded. One of the three phases has a smaller spark than normal, while the other has a larger spark than normal. In the auxiliary circuit of electrical equipment, if the armature of the contactor coil circuit can't attract well after being electrified, if you want to get angry, it's because the mechanical part of the contactor is stuck or the circuit is broken, you can start the start button. If there is a slight spark in the closed position of the button when it is disconnected, it means that the circuit is still in the path state, and the fault is caused by the mechanical part of the contactor. If there is no spark between the contacts, the circuit is in an open state.
Second, the principle of electrical equipment maintenance
After finding the fault causes of electrical equipment, it is necessary to maintain electrical equipment, which requires a detailed understanding of the maintenance principle of electrical equipment. The maintenance principles of electrical equipment mainly include: (1) Before starting the maintenance of electrical equipment, the electrical equipment should be inspected in detail. Once the electrical equipment fails, it is not necessary to carry out the maintenance of the electrical equipment blindly at the beginning, but to carry out a detailed inspection first. Find out the fault causes and specific fault parts of electrical equipment, and then start the maintenance of electrical equipment. If you want to repair some unfamiliar electrical equipment, you must first understand the circuit structure and circuit principle of the electrical equipment in detail, and then you can carry out maintenance work according to the corresponding maintenance procedures. (2) The order principle of equipment maintenance is to repair the external equipment first, and then repair the internal structure. Before maintenance work, the external structure of electrical equipment should be checked, and the external conditions such as maintenance history, service life and defect status of the equipment should be known in detail. After troubleshooting the peripheral equipment, only after troubleshooting the external equipment can the internal equipment be disassembled. (3) The mechanical equipment in the electrical equipment shall be maintained first, and then the electrical equipment shall be maintained. When checking the circuit fault, carry out professional detection to find the exact location of the fault, and then carry out the maintenance of electrical equipment after confirming that there is no problem with the mechanical equipment to ensure the accuracy of equipment maintenance; (4) The maintenance of electrical equipment should be static before dynamic. When the equipment is not electrified, the relay, contactor and other equipment should be repaired first, and then the equipment should be electrified to find the corresponding fault point for maintenance; (5) Before equipment maintenance, the equipment must be cleaned. In practical work, many equipment failures are caused by serious equipment pollution, which requires cleaning the equipment before equipment maintenance to eliminate external failures; (6) Maintain the power supply first, and then maintain other equipment. In the actual work process, the probability of power failure is very high. Before electrical equipment maintenance, do a good job of maintaining power supply to eliminate the impact of power failure on the normal operation of electrical equipment.
Third, the maintenance of electrical equipment
Once the electrical equipment breaks down, it will have a great impact on the normal production and life of users. In order to effectively prevent the failure of electrical equipment, it is very necessary to do a good job in the maintenance of electrical equipment. When doing the maintenance of electrical equipment, we should first make clear the consequences and causes of various faults in the system, test the functions of the system, and take corresponding effective preventive measures to maintain the equipment according to the causes of various faults. At present, there are still some problems in the maintenance of electrical equipment in most enterprises in China. In the maintenance of equipment, the traditional maintenance method of regular maintenance often has a certain lag. Many enterprises do not pay enough attention to equipment maintenance, and the overall quality and professionalism of the selected equipment maintenance personnel are not high. In view of the problems existing in electrical equipment maintenance, the following measures can be taken to improve it: (1) Organize technical training for maintenance personnel regularly, improve the overall quality of electrical equipment maintenance personnel, strengthen professional skills training, and enhance the professional skills of maintenance personnel; (2) adopt modern maintenance means and advanced science and technology to dynamically overhaul the use of equipment, adopt some intelligent maintenance means to find problems in time, and timely maintain and repair the equipment to ensure that the working efficiency of the equipment is not affected; (3) Establish a clear electrical equipment maintenance system and clarify the responsibilities of each equipment maintenance personnel, so that electrical equipment maintenance personnel can complete equipment maintenance work in strict accordance with certain rules and regulations and maintenance principles, and improve the equipment maintenance effect.
Concluding remarks
With the rapid improvement of people's living standards, the number of electrical equipment is also increasing rapidly. In the use of electrical equipment, various faults often occur. This requires that equipment maintenance should be done well according to the principle of equipment maintenance, and at the same time, equipment failure should be prevented, the normal operation of equipment should be prevented from being affected, and the normal working efficiency of equipment should be ensured.
refer to
[1] sheets. Analysis on Maintenance Principles and Inspection Methods of Electrical Equipment [J]. Electronic Manufacturing, 20 13(4).
[2] Zhang Wei. On the principle and maintenance of electrical equipment [J]. Private Science and Technology, 20 12(9).
[3] Tang Yandong. Reliability and Maintenance Analysis of Enterprise Electrical Equipment [J]. Technology Entrepreneur, 20 12( 10).
Electrical Equipment Maintenance Technology Paper II Analysis of Electrical Equipment Maintenance Strategy
Various problems will occur in the operation of electrical equipment. When these problems occur, the most important thing is maintenance. Electrical equipment maintenance personnel should first find out the cause of electrical equipment failure, then repair the electrical equipment, and finally let the electrical equipment run to see if the previous failure has been completely solved. To do electrical equipment maintenance well, electrical maintenance personnel need to have a lot of practical experience and be very familiar with electrical maintenance knowledge. In addition, electrical equipment maintenance personnel need to constantly explore and learn to improve the maintenance level of electrical equipment, so as to better serve the general public.
Electrical equipment; Maintenance principle; Methods; tactics
1 electrical equipment maintenance principles
1. 1 talk before you do it.
For faulty electrical equipment, we should not rush to start work, but should first ask about the process and phenomenon of the fault. For unfamiliar equipment, we should also be familiar with the circuit principle and structural characteristics and abide by the corresponding rules. Before disassembly, you should be fully familiar with the function, location, connection mode of each electrical component and its relationship with other surrounding equipment. In the absence of assembly drawing, you should draw a sketch and mark it when disassembling.
1.2 Cleaning before maintenance
For heavily polluted electrical equipment, first clean the buttons, connection points and contacts, and check whether the external control keys are out of order. Many faults are caused by dirt and conductive dust.
1.3 General use first, then special use.
Faults caused by the quality of assembly parts or other equipment faults generally account for about 50% of common faults. The special faults of electrical equipment are mostly soft faults, which need to be measured and maintained through experience and instruments.
1.4 machinery precedes electricity.
Electrical inspection can only be carried out after the mechanical parts are confirmed to be trouble-free. When checking the circuit fault, it is necessary to find the fault position with testing instruments. After confirming that there is no poor contact fault, it is necessary to check the operation relationship between the circuit and the machinery in a targeted manner to avoid misjudgment.
1.5 External precedes internal.
Check the equipment for obvious cracks and defects, understand its maintenance history and service life, and then check the inside of the machine. Before disassembly, the peripheral fault factors should be eliminated, and the equipment can be disassembled only after the internal fault is determined, otherwise it may get worse and worse if the equipment is disassembled blindly.
1.6 Static before dynamic
When the equipment is not energized, judge whether the buttons, contactors, thermal relays and fuses of the electrical equipment are good or bad, so as to determine the fault. Power-on test, listen to its voice, measure parameters, judge faults, and finally carry out maintenance. For example, when the motor is out of phase, if the measured three-phase voltage value can't be judged, you should listen to its sound, measure the relative ground voltage respectively, and judge which phase is defective.
1.7 equipment front power supply
The failure rate of power supply is very high in the whole faulty equipment, so it is often twice the result with half the effort to repair the power supply first.
2 Maintenance methods of electrical equipment
2. 1 intuitive method
What is the intuitive method? The intuitive method is to judge what is wrong with the electrical equipment by observing the running state and listening to the running sound of the electrical equipment. Visual inspection steps: Step 1, let Electric equipment manager introduce the basic situation of electrical equipment operation, and what is the difference between the operation state of electrical equipment and the previous operation state after the fault occurs. For example, whether there is abnormal sound when the electrical equipment is running, and whether there is water intrusion inside the electrical equipment; Step 2, check whether there are cracks, scratches and other damages on the outside of the electrical equipment, whether the parts of the electrical equipment are loose or lost, and whether the internal wiring is entangled or broken. The third step is to carry out trial operation inspection. And check whether the placement of internal parts of electrical equipment is different from the contents marked in the design drawing, and finally confirm the fault.
2.2 Voltage and current measurement methods
Measure the voltage and current values in the circuit, and compare the measurement results with the normal voltage and current values, and judge the faults of electrical equipment according to the comparison results. There are three ways to measure voltage and current: 1. Divide the circuit into several sections and measure the voltage and current of each section; 2. Find several important points in the circuit and measure the current and voltage values of these points; 3. Step measurement method.
2.3 Method of measuring resistance
The method of measuring resistance is generally used for electrical equipment with large volume and long component spacing.
2.4 Original conversion method
Why use the original conversion method? Because the circuits of some electrical equipment are complicated, it is difficult for maintenance personnel to sort out a correct idea. In this case, you can replace some parts that are prone to failure in the original factory, and then run the electrical equipment for inspection. When using the original factory conversion method, it is very important to pay attention to: when replacing the original factory, you must check the circuit to see if there is any abnormality in the circuit. This is done to prevent the faulty circuit from burning the original, thus reducing the expenses of the enterprise on the original.
2.5 forced closure method
Under what circumstances is it easy to use forced closure method? This method is generally used when there is no available instrument around to check the electrical equipment, and it is difficult to judge what is wrong with the electrical equipment by asking and viewing. The specific operation steps of forced closure method: step one, press the relay or contactor with insulation; The second step is to judge what is wrong with the electrical equipment by looking at the operation of each part of the electrical equipment.
2.6 short circuit method
Short circuit method is generally used to check the open circuit fault of electrical equipment. Open circuit fault includes many kinds of fault conditions, such as broken wire, poor contact at the end of the wire, weak welding and so on. The specific operation steps of short circuit method: first, think about which parts of the circuit are easy to open; Step 2, connect the parts that are prone to open circuit failure thought in step 1 with lines without problems; The third step, after the short circuit, the electrical equipment can run normally, indicating that there must be something wrong with the short circuit in the second step.
2.7 Step-by-step open circuit (access) method
Step-by-step open circuit (access) method is generally used for electrical equipment with complex circuits and many branches. When the electrical equipment containing this circuit fails, there is no abnormal external performance. Step-by-step open circuit operation steps: disconnect the AC circuit step by step, and then conduct a power-on experiment. If the fuse is disconnected, the problem is on the newly disconnected line. Step-by-step access method operation steps: first, disassemble each branch in the circuit, and then connect the branch to the power supply step by step to carry out the power-on experiment. If the fuse is open, it means that the problem is in the branch just connected.
3 Maintenance strategy of electrical equipment
Once the electrical equipment breaks down, it will have a great impact on the normal production and life of users. In order to effectively prevent the failure of electrical equipment, it is very necessary to do a good job in the maintenance of electrical equipment. When doing the maintenance of electrical equipment, we should first make clear the consequences and causes of various faults in the system, test the functions of the system, and take corresponding effective preventive measures to maintain the equipment according to the causes of various faults. At present, there are still some problems in the maintenance of electrical equipment in most enterprises in China. In the maintenance of equipment, the traditional maintenance method of regular maintenance often has a certain lag. Many enterprises do not pay enough attention to equipment maintenance, and the overall quality and professionalism of the selected equipment maintenance personnel are not high. In view of the problems existing in electrical equipment maintenance, the following measures can be taken to improve it: (1) Organize technical training for maintenance personnel regularly, improve the overall quality of electrical equipment maintenance personnel, strengthen professional skills training, and enhance the professional skills of maintenance personnel; (2) adopt modern maintenance means and advanced science and technology to dynamically overhaul the use of equipment, adopt some intelligent maintenance means to find problems in time, and timely maintain and repair the equipment to ensure that the working efficiency of the equipment is not affected; (3) Establish a clear electrical equipment maintenance system and clarify the responsibilities of each equipment maintenance personnel, so that electrical equipment maintenance personnel can complete equipment maintenance work in strict accordance with certain rules and regulations and maintenance principles, and improve the equipment maintenance effect.
4 conclusion
Analyze and process the information provided by daily maintenance, routine inspection, regular key inspection, online condition monitoring and fault diagnosis of equipment, judge the deterioration and development trend of equipment health and performance, and plan the maintenance of equipment before the failure occurs and the performance drops to the allowable limit. Point inspection and repair, fault diagnosis and condition maintenance are a whole, and the essence is to find, analyze and solve problems. Without complete and useful data collection, it is impossible to find the problems existing in the equipment in time. After the problem is found, it should be analyzed and studied in time to find out the cause of the fault, the law and mechanism of development and change. Condition-based maintenance (CBM) is an optimal maintenance method to solve equipment faults reasonably and economically.
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[1] Liu Heze, Research on Condition-based Maintenance Strategy of Electrical Equipment [J], Modern Economic Information, 2009, (17)
[2] Yang Zhong, Discussion on Equipment Maintenance Strategy 20 10/0.