Maintenance Guide for High Power Switching Power Supplies
With the development of modern electronic technology, electronic devices have become increasingly complex, thus requiring higher load requirements for power supplies. Although traditional regulated power sources have better stability and are more reliable to use, they require large and heavy transformers and filters, making it difficult to meet the flexibility requirements. At this point, the advantages of switching power supply begin to emerge, as it has been applied in a wider range of fields with the advantages of small size, light weight, and high efficiency. For the control and protection of high-power switching power supplies, we should master some knowledge about their faults and maintenance to ensure the reliability of the power supply during use.
The first possible fault is the fuse burning or tube explosion of the power supply. Our maintenance work should follow the following steps: first, we should mainly inspect key parts such as the rectifier bridge, diode, and large filter capacitor. If no problems are found, then check the anti-interference circuit for any problems.
The second type of fault is that the fuse is normal, but the power supply still has no voltage output. This is when we should first measure whether there is a starting voltage. If the voltage is zero or very low, we should check if there is any component leakage in the starting pin, so that the faulty part can be detected. If there is a startup voltage, it is possible that there is a malfunction in the control chip or protection circuit. At this time, we can investigate one by one to identify the fault.
The third type of fault is that the voltage output by the power supply is too high. The reason for this failure is usually a problem with the voltage regulator control circuit, which may occur in any component in the closed circuit, including optocouplers, control chips, etc. The fourth type of fault is exactly the opposite, which is that the voltage output by the power supply is too low, and there are various reasons for this situation. One is a short circuit in the circuit; Secondly, the conduction function of the switch tube fails, resulting in an increase in the internal resistance of the power supply and a decrease in the output voltage; Thirdly, the poor operation of the 300V filter capacitor results in a decrease in the load capacity of the power supply; Fourthly, there is a problem with the switch transformer.
In many cases of malfunction, if there is a problem with the switch tube, it is necessary to immediately cut off the power supply, otherwise it may easily cause the switch tube to burn out. After disconnecting the power supply, we will replace the switch tube and conduct other troubleshooting.
In some high-power applications, the loss of switching power supply is very high, which can easily lead to overheating and component burnout. For some complex repairs, professional maintenance personnel are required to troubleshoot and repair faults. In order to solve these small problems and troubles during use, it is very important to master some necessary circuit principles and maintenance knowledge.
