Taking AV2 vector frequency converter as an example, this paper introduces that when the frequency converter fails, the protection function will act, the frequency converter will trip immediately, the motor will stop from running state, the red LED for alarm indication will turn on, and the LCD part will prompt the alarm information code or fault content. At this time, the fault range of the inverter can be analyzed and judged according to the information code. If it is a soft fault, the inverter can be powered off and reset. If it can not return to normal, it can only be initialized manually or automatically. After the initialization is normal, the data will be input and set again according to the parameter table. In this way, the inverter can return to normal use when the fault is light. If the frequency converter is still abnormal after the above operation, it is necessary to check the damaged parts of the frequency converter according to the fault phenomenon and replace the components or circuit board. The fault finding must be carried out according to the prompt sequence of frequency converter.

For example:

(1) The fault code is 12, indicating that the inverter is overloaded.

(2) Fault code 20, current detection error

(3) Fault code 23, PID feedback disconnection

If the current limiting alarm or over-current protection occurs frequently during the operation of the frequency converter, check whether the load part and IGBT module of the frequency converter are normal. If they are normal, the fault is that the Hall magnetic compensation current sensor of the main board of the frequency converter is damaged. Hall magnetic compensation type current sensor is a kind of current value measuring sinusoidal and non sinusoidal periodic quantity, which can truly reflect the current waveform and provide a control and protection signal for frequency converter.

The production operation shows that the corrosive gas containing hydrogen sulfide in viscose fiber production site will bring considerable harm to the electronic components of inverter circuit board. We improve the environmental conditions by sending positive pressure fresh air to the electrical control room, and use loctite electronic circuit board spray glue to treat the surface of inverter circuit board with anti-corrosion coating, which effectively reduces the fault of inverter The service life is improved.

Electronic components are very sensitive to static electricity. If damaged by electrostatic discharge, it will cause soft breakdown of electronic components, which will lead to the circuit board can not work normally. Therefore, when replacing the circuit board, we must pay attention to ensure that we wear the grounding Bracelet before work, and directly ground the wristband, so as to ensure that the human body is at zero potential, so as to prevent damage to the circuit board caused by static electricity of the human body. If there is no grounding bracelet, when replacing the circuit board, you can touch the metal shell of the inverter to let the static electricity of the human body go through the inverter shell (the metal shell conducts static electricity). In order to ensure the safety of inverter circuit board spare parts, they should be stored in bags with anti-static materials during storage.

Editor in charge: yyx

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