Inverter maintenance is combined with a theoretical knowledge, practical experience and operational level work, the technology level determines the quality of maintenance of the drive. In inverter maintenance personnel need often learn to understand the inverter's internal electronic components of the capabilities and features to develop their knowledge, the newly acquired knowledge to practical work and constantly improve the technological level of maintenance of common ways to edit static Test 1, Test rectifier circuit looking at the results, you can determine the circuit is abnormal, A. to P terminal and N-terminal of the inverter internal DC power supply, the multimeter X10 file transferred to the resistance, the red bar received P, black bars respectively, according to the R, S, T, normally when there are dozens of Europe's resistance, and balance. Instead the black bars connected to the P-side, the red bar depending on drive repair image converter maintenance pictures (5) times received R, S, T, there is a close to infinite resistance. The red bar connected to the N-terminus, repeat the above steps should get the same result. If there is resistance to phase unbalance, indicating the rectifier bridge is faulty .B. Red when connected P rod end, infinite resistance, it can be concluded rectifier bridge failure or failure of a startup resistor. 2, the test inverter circuit connected to the red table rod P side, black bars are connected to U, V, a W, there should be dozens of Europe's resistance, and the resistance of each phase is basically the same, RP should be infinite. The black bars N terminal, repeat the above steps should get the same results, or may be determined faulty inverter module. Dynamic test result is normal after the static test, dynamic test can be conducted, that power test machine. Before and after the power must note the following: 1, before power, be sure the input voltage is wrong, will appear 380V power access into the bombing 220V class inverter (fried capacitors, varistors, modules, etc.) ; 2, check whether the drive each jack is properly connected, the connection is loose, the connection may sometimes cause abnormal drive failure, and in severe cases the bombing and so on; 3, after the power failure detection display, and preliminary determination and the reasons for failure; 4, If it does not malfunction, first check whether there is an exception, and the arguments after reversion, the no-load (no connection motor) start the drive case and test the U, V, W phase output voltage value. In case of phase loss, phase imbalance, the module or driver board are malfunctioning; 5, when the output voltage is normal (no phase, three phase), the load test, try a full load test. [1] The fault diagnosis 1, rectifier damage is usually caused by grid voltage or an internal short circuit. The exclusion of an internal short circuit, replace the rectifier bridge. When the scene failure, should focus on checking the user grid conditions, such as grid voltage, with or without the grid welding machine and other polluting equipment. 2, inverter module damage is usually caused by damage to the motor and drive circuit or cable fault. After the repair the drive circuit, the measured drive waveform good condition, replace the module. After replacing the drive plate in field service, and must pay attention to check the motor and connection cable. In determining without any failure to run the drive. 3, no display power switching power supply is usually caused by damage or soft charge circuit damage caused by the DC circuit without DC, such as the startup resistor is damaged, the control panel will produce the same damage this situation. 4, over-voltage or under-voltage display usually due to input phase, circuit and circuit board damp caused by aging. The solution is to find out the voltage detection circuit and the detection point, the replacement of defective devices. 5, showing an overcurrent or short circuit to ground is usually due to the current detection circuit is damaged. Such as Hall elements, op-amp circuit. 6, power supply and start-up display driver board is usually caused by over-current drive circuit or inverter module damage caused. 7, no-load output voltage is normal, after load an overload or overcurrent is usually due to improper parameter setting or driver circuit aging, causing damage to the module. .