Maintenance of Common Faults in Electrical Technology Experimental Device

abstract

This paper summarizes the common fault phenomena, fault causes and maintenance methods of electrical technology experimental devices, including the common faults of adjustable DC regulated power supply, three-phase power supply and IGBT components, and summarizes the general steps and methods of fault diagnosis and treatment. Some principles of equipment maintenance are also analyzed, which has a good reference significance for the daily maintenance of electrical equipment.

Keywords: failure analysis and maintenance methods of electrical technology experimental device

1 Common troubleshooting methods

Common faults of 1. 1

We often encounter some faults when conducting electrical technology experiments. If you are not familiar with the forms and causes of these faults, you can't determine the causes of the faults and solve them smoothly, thus affecting the progress of the experiment and the accuracy of the experimental results. Through the analysis and summary of a large number of electrical technology experiments, we found the following common and typical failure forms: ① power failure. This mainly shows that the voltage provided by the power supply to the electrical technology experimental device is unstable, high or low, and the current phase of the AC power supply does not meet the requirements. ② Line failure. Line faults are common in electrical technology experiments, mainly manifested as short circuit caused by wiring errors and open circuit caused by poor line contact points. In addition, line faults may also cause adverse effects such as local leakage. ③ Component failure. The failure of components themselves is also a major reason for the failure of electrical technology experiments. Some sensitive components which have strict requirements for experimental conditions may lead to the failure of components and affect the experimental process once their test methods do not meet the requirements or the experimental environment does not meet the standards.

1.2 troubleshooting steps

Based on the long-term analysis and research of the experimental fault forms and the experience of actual fault maintenance, we summarize the following methods and steps to analyze, judge and deal with the common faults in electrical technology experiments:

Investigation on 1.2. 1

When we encounter a fault in the electrical technology experiment, we should first carefully observe the location, form and corresponding abnormal phenomena of the fault. For example, if there are abnormal phenomena such as fever, pungent smell, abnormal vibration and loud noise in the experimental device, we can make a general analysis and judgment on the fault phenomenon, location and nature through our sensory organs, which will provide reference for the subsequent analysis and treatment.

1.2.2 fault analysis and judgment

After making a preliminary judgment on the experimental fault, we should further analyze and judge the cause and location of the fault according to the existing knowledge and experience. To this end, we can use the troubleshooting method. For example, when a loop or element of a faulty circuit is cut off or short-circuited, whether the current and voltage values of the loop or element conform to the theoretical values are measured, and then the fault position of the loop is determined step by step. At the same time, in order to judge whether a component is faulty or abnormal, normal components can be used instead of detection, and whether the voltage and current parameters of the circuit before and after are consistent can be compared to judge.

1.2.3 fault maintenance

After finding out the cause and location of the fault through the above steps, it is necessary to repair the fault. If it is due to the failure of experimental components, it is necessary to replace the experiment with normal components if necessary. If it is a short circuit or an open circuit fault, it is necessary to reconnect the circuit and continue the experiment after the test is normal. In order not to affect the progress and results of the experiment, we should try our best to adopt direct, effective, convenient and fast methods to repair the experimental faults. If necessary, we should redesign the circuit structure, use highly reliable components, and restart the experiment after all faults are eliminated.

2 DC regulated power supply

Electrical technology experimental devices include adjustable power supply, adjustable current source and adjustable voltage source. The former can output a stable current signal to the circuit, and the latter can add a stable voltage at both ends of the external load. Taking DC regulated power supply as an example, the common faults are as follows:

(1) DC current source can't output current, or the current provided is very small, close to zero. The general reason is that the current source switch is turned on, but the external load is not turned on, which leads to the overload of the current source and the start of the internal protection device to prevent the circuit from overheating and burning.

The solution is to cut off the main power supply, let the system cool for a period of time, so that the memory of the memory device disappears completely, then turn on the power supply, carefully check the external circuit to ensure the smooth access of the external load, and finally turn on the current source switch to troubleshoot.

(2) The 2)DC regulated power supply does not output voltage signals. Generally, this happens. It is likely that the two ends of the voltage source are short-circuited when connecting the circuit, resulting in excessive current, internal protection mechanism working and voltage signal interruption. Similar to (1), it is necessary to cut off the main power supply, turn on the power supply again after cooling, adjust the external circuit configuration, and then turn on the voltage source to resume normal operation.

(3) The regulation ratio of the output voltage of the voltage source is reduced. Under normal circumstances, the output voltage of the voltage source can be smoothly adjusted between 0 V and 30 V, and the power supply adjustment range will be greatly reduced when a fault occurs. After careful investigation, the voltage source above is normal, but the circuit below is faulty. First, check the circuit board corresponding to the upper and lower voltages, first confirm that the circuit board is fault-free, then check the connecting line between the potentiometer and the circuit board, and finally check the potentiometer, and find that the resistance value of the potentiometer is abnormal. After determining the cause of the fault, the potentiometer was replaced and the fault was eliminated.

3 adjustable resistance

A large number of adjustable resistors are distributed on the base of the experimental device, with resistance values ranging from 0 ohms to 900 ohms, and these components are also prone to failure.

3. 1 Common faults

Under normal circumstances, the resistance between the two terminals is infinite, and it is possible that the current is too large and the adjustable resistance fuse is burnt out, as long as a new fuse is replaced; Another reason is that the resistance wire of adjustable resistance has been worn for a long time, and some resistance wires are broken, which leads to the disconnection of the circuit, so it is necessary to replace the whole adjustable resistance hardware.

3.2 solutions

When troubleshooting, first take out the adjustable resistance fuse and check whether it is open. If it is open, replace it. If the open circuit fault is eliminated, check the on-off condition of the adjustable resistor itself. If it is confirmed that the adjustable resistor device has been turned on, it needs to be replaced with a new device.

4 Matters needing attention in fault maintenance

In the process of fault detection, analysis and maintenance, in order to ensure the personal safety of experimenters and the rationality and effectiveness of detection and maintenance, we need to pay attention to the following requirements: First, in the process of detection and maintenance, we must strictly abide by the relevant experimental operating procedures and steps. At the same time, it is necessary to ensure that the use conditions and methods of experimental instruments and equipment meet the requirements. Second, we should always attach great importance to the personal safety of the operators when repairing the faults of electrical technology experiments. We should not only pay attention to the improvement of maintenance skills, but also pay attention to the education of safety operation awareness. Third, we should pay attention to summarize and analyze the new situations and problems in the process of fault maintenance, constantly learn new technologies and knowledge, expand maintenance skills and test them in practice. Only by strengthening study and active practice can we calmly deal with the fault maintenance of electrical technology experimental equipment.

refer to

[1] Lan Xiaowei. On the principles and methods of electrical equipment maintenance and inspection [J]. Private Science and Technology, 20 10(04).

Hu longbin Common maintenance methods and practices of electrical equipment [J]. Heilongjiang Science and Technology Information, 2007( 14).

[3] Zhang Jian. Common maintenance methods and practical details of electrical equipment [J]. Heilongjiang Science and Technology Information, 2009( 10).

[4] Xu Peng. Analysis and solutions of common faults of electrical equipment [J]. Heilongjiang Science and Technology Information, 20 1 1(2 1).

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