When the switch power supply is checked, the filter coil burning phenomenon of the power supply is often found, and the PCB plate around it is carbonized. The filter coil wire diameter thick, but the actual use is not present in the current overload. What's the reason for this?
The line diameter is not necessarily a problemNow cheaper power, the device also needs to be cheaperThere is also a copper wire winding, copper clad aluminum, more use of aluminum. With aluminum instead of copper wire, heating as can be imagined.And then there's the magnetic core, which is the most difficult to distinguish. How do you make sure that the core is better?From the picture, it should be caused by long-term high temperature bakingFrom the picture, the power of the above fifty or sixty watts to one hundred or two hundred watts in Shenzhen, under the consideration of power, voltage and current, inductance selection here there may be a problem. Or the materials used. The filter inductor plate, other parts have no problem?The nominal temperature of the electrolytic capacitor is 85 degrees, 105 degrees. Use some of the company's capacitors. Of course, consider how long the power has been usedPCB is the cardboard. It must be of poor quality
Oh, man, you agree to the above answer, this should be a conventional switching power supply 24V 10A, the board have done bad, domestic plagiarism is very serious, some plant engineers are halfway started to engage in this power, the last problem does not work but also ask our electronic transformer engineer. Shows how poorly designed at the time. The output filter inductance in the figure should be QZY high temperature wire, is also illuminated because it is at 100 DEG C for long-term work is simply a pediatrician, but the capacitance, paper based around PCB can't stand the long-term high temperature, so the carbon black, bulging and so on, it is also happy to see manufacturers, too a period of time, you have to get the factory maintenance, or buy a piece of power for you for 10 years, I have to earn money! It is estimated that customers are under full load for long periods of use. Even if you replace the new electrolysis, less than half a year will drum up the package. The fundamental solution to the problem is to redesign the board, or to change the electrolysis, but it's impossible for the most profitable manufacturers! Therefore, it is recommended to communicate with the customer, change a power supply or put the power in a lower temperature environment. Above personal opinions, welcome to adjust, check missing, ha ha.If you have any questions, please ask me at the big bit forum. If you help me, I hope to adopt the answer!
According to the picture, it can be seen at once that the design parameter of the reactor (filter coil) is the problem. Simply speaking, the inductance of the reactor is large, the pressure drop is large, the magnetic flux is large, the core is saturated, the magnetic loss is too large, and the heating is on the reactor itself. If the circuit does require that much inductance, replace the core of another material or use a larger core. In fact, this simple switching power supply filter inductance is not very accurate, in order not to heat, it is appropriate to reduce the number of turns around it.
Control circuit problems, limiting voltage is not controlled, resulting in excessive output voltage, otherwise the capacitor will not drum up. Filter coil enameled wire is relatively coarse, but also burned so seriously, mostly for long-term excessive current caused by the focus of the inspection circuit.
