June 13, 2023
The duty of a repair electrician is to ensure normal operation of various types of engines and their electrical control systems and industrial and residential lighting systems in motion of various industrial machines.
As a maintenance electrician, in addition to reasonable installation of equipment and lines, good debugging and daily maintenance and inspection, when a malfunction occurs, he can quickly find out cause of malfunction and correct malfunction. guarantee of normal operation of equipment.
Troubleshooting skills are very important for maintenance electricians, mainly in following aspects:
1.Equipment failure due to failure sometimes causes large economic losses and affects labor efficiency of enterprise.Therefore, technical requirements for repair electricians to troubleshoot are very high.
2. For electrical faults with a wide range and high randomness, ability to troubleshoot is main characteristic of profession (type of work) of a maintenance electrician, and also puts forward higher requirements for skills of a maintenance electrician to troubleshoot. .
3. In addition, whether it is professional standards or skills assessment, although troubleshooting assessment has a certain degree of contingency, it reflects comprehensive skills of maintenance electrician and reflects characteristics of profession (job type) Therefore, project assessment is still ongoing. And often set elements of error queue to be "negative elements". That is, if assessment fails, entire assessment will be considered non-qualified.
In real operation, electrical faults occur in a wide range, affecting every part of electrical system, and faults are constantly changing and random. The troubleshooting method can only be determined according to specific fault situation, and there is no strict fixed mode, which confuses some maintenance personnel. They often make many detours in troubleshooting process, and even cause large losses.
The following are common problems in its electrical control system, and industrial and residential lighting systems, which can be discussed with colleagues in order to learn, promote and improve each other.
1. Basic troubleshooting
In order to completely eliminate malfunction, cause of malfunction must be clear. In order to find out cause of malfunction quickly, in addition to constantly gaining experience in work, it is more important to be able to analyze and explain cause of malfunction theoretically, i.e. “to know, of course, you also need to know why, use theory to guide your own operations, and flexibly use a variety of failure queuing methods.
1. Possess certain professional theoretical knowledge. For many electrical phenomena, it is necessary to have advanced professional theoretical knowledge in order to really understand and understand. Compared to other types of work, electrical repairmen are more theoretical, sometimes without theoretical guidance, many jobs cannot be done at all.
In real work, it often takes more time to think than to actually do it. Once fault is found, repairs are relatively easy. It is necessary to consider some basic concepts about "principle of self-control" and principle of operation of system in order to achieve a better understanding and mastery.
For example, when incandescent lamps are connected in series with diodes, life of lamps can be greatly extended, and concept of relationship between temperature change and resistance value must be used. Without certain professional knowledge, it is impossible to truly understand and master certain issues.
2. Understand movement form of equipment, electrical requirements, understand and master electrical working principle of equipment, master electrical working principle, and compare electrical characteristics of equipment control, which is very important. important basis for troubleshooting.
Acquaintance with main content of composite equipment control system and electrical control technology, understanding their typicality, completeness and complexity. Really master system troubleshooting skills of typical equipment and be able to draw conclusions when encountering other equipment.
When a system fails, it often affects a large range. If you do not know electrical principle of equipment, you will not be able to troubleshoot well or even be unable to troubleshoot.
3. Understand specific position of each electrical component in equipment and circuit layout, and recognize one-to-one correspondence between electrical circuit diagram and actual wiring, which is basis for improved troubleshooting. speed. By doing this, you can get a better understanding of hardware, and when troubleshooting andmeasurement, you can select effective breakpoints to prevent erroneous estimates, to quickly evaluate and narrow down area of faults.
Second, general troubleshooting method
Have a certain theoretical background, master principle of operation of equipment and conduct a complete preparation for troubleshooting. To effectively analyze and find out location of a malfunction, it is necessary to have certain tools, which is a general troubleshooting method.
1. Resistance Method: Usually refers to method of using a multimeter's electrical barrier to measure whether a circuit, contact, etc. is on or off. Sometimes resistance value of a coil is also measured with a multimeter or bridge. Whether it matches rated value, also use a megger to measure insulation resistance between phase and phase, phase and earth, etc.
When measuring, pay attention to range selection (in general measurement channels, select a lower gear); compare table; pay attention to presence of other circuits so as not to cause an incorrect assessment; should pay more attention paid to strictly prohibit real-time measurement, which is a kind of widely used method.
2. Voltage method: refers to method of using appropriate multimeter voltage block to measure voltage value in a circuit. Usually, when measuring, sometimes measure voltage and load voltage (that is, keep eating and drinking between two load test leads, and sometimes measure open circuit voltage to determine if line is normal.
Pay attention to position of meter gear when measuring, select appropriate range, and pay attention to positive and negative polarity when measuring DC current. This is also more common method.
3. Current measurement method: Determine cause of fault by measuring whether current in line is normal. Low current circuits are often measured by connecting an ammeter or multimeter in series with a current block in circuit, and high current circuits are often detected with current clamps.
4. Replacement Method: If you suspect a certain device is faulty but cannot be sure and spare parts are available, you can replace test to see if problem is fixed.
5. Short circuit method: Suitable for low-voltage and low-current circuits, short-circuit points method with moderate emotions thick wires for testing. However, it must be determined that a short circuit will not cause a short circuit, and if it works after a short circuit, it will not cause harm. Live shorting is prohibited and generally beginners should not use it.
6. Direct check method: after understanding cause of failureEquity or based on experience, likelihood of frequent faults is high, and there are some special faults, you can directly check suspected fault. dot.
7. Instrument test method: use various instruments to measure various parameters, such as using an oscilloscope to observe change in waveform to analyze cause of failure. It is mainly used in low current lines.
8. Step-by-step troubleshooting method: If a short circuit occurs, some lines can be gradually turned off to determine fault range and fault point.
9. Parameter setting method: some components in circuit are not damaged, and connection in circuit is good, but it is only related to some physical quantities (such as time, offset, current, resistance value, temperature feedback signal strength, etc.). etc.) ) are not properly adjusted, so system cannot work normally. At this time, it should be adjusted according to original electrical work pattern and specific conditions of equipment.
10. The method of comparison, analysis and judgment: it is based on principle of operation of system, program of actions of control link and logical relationship between them, combined with phenomenon of malfunction. , for comparison, analysis and judgment, cut measurement, inspection and other references, and quickly determine extent of fault.
For example, if several lines use same power supply, while one line is working normally, this means that power of other lines is normal; between control lines in two places, if one control line is normal, that means there should be no problem with power supply, load and public line.
Assessment based on analysis and comparison can reduce number of links to review, reduce errors, and speed up troubleshooting. It is suitable for directly identifying fault area or fault point of some lines, and also needs to go through whole troubleshooting process.
The above several commonly used methods can be used alone or in combination, and should be used flexibly in conjunction with specific situations.