This article discusses the repair process and failure analysis of the Schneider ATV71HD18N4Z drive. For reference.
Shanghai Jinxin Inverter Technical Service Center recently received the Schneider ATV71HD18N4Z inverter. The customer's response is that the inverter has no display failure.
Inspection process:
Remove the lower cover plate of the inverter and check the rectifier module and inverter module of the inverter. The test diode has good characteristics. The inverter will be powered, no display, there is no 24VDC voltage on the test control control terminal, there is no +5VDC voltage on the control card. Inverter fan power transmission is not running, judge the inverter switching power supply is damaged.
Failure Analysis:
To disassemble the inverter, by the way, the disassembly of the inverter in this structure is complicated because the upper cover is not particularly easy to disassemble. There is a large scorch mark near the inverter's power card pulse frequency converter. Obviously, the load of the switching power supply is short-circuited, causing the switching power supply to fail to work. Remove the power supply card and trigger the inverter module. The inverter module is good. The power supply card is handled cleanly and it is found that there are many traces of corrosion on the components of the power supply card. It is estimated that the inverter is used in occasions where there is corrosion.
Due to the corrosion of the power supply card of the inverter, there is a relatively large chance that the switching power supply is short-circuited. The inverter's switching power supply is damaged due to a short circuit on the inverter power supply card.
Repair process:
Clean the power card, replace the damaged diode, and repair the damaged circuit. Power test, found that the switching power supply is still not working properly, after a while also found that the replacement of the diode was damaged. Continuing to find the line, it was found that there was a 7915 short circuit on the line load, and the 7915 was replaced and the damaged diode was replaced. After the power board is tested and the power is turned on, the power of each channel of the switching power supply is working properly. The IGBT driving circuit is tested, and the respective trigger circuit is working properly. With the inverter installed, the test diode has normal characteristics. Power transmission to the inverter, start-up, output voltage balance, with load to rated current, inverter heat is normal, the inverter repair.
Experience summary:
Shanghai Jinxin Inverter Service Center based on years of experience with Schneider's inverter maintenance, concluded that this fault is caused by the inverter corrosion.
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