The frequency converter has the effect of protecting the machine, which is all known to all. But you know, in fact, we regularly check the frequency converter we use, and we are giving the machine the greatest protection. In order to ensure that the machine can be used normally under the protection of the frequency converter, the frequency converter used by us should be checked regularly. Then check out from what aspects of the initial start, the following is simply to say to you:
(1) for regular inspection, before the operation is necessary to cut off the power supply, inverter power after the operation panel power indicator subsided, waiting for 4min (inverter capacity is more big, wait for a longer time, the length of 15min) to fully discharge the main circuit of DC filter capacitor, with a multimeter that capacitor discharge after re operation. This is very important!!!
(2) remove the converter control board and the main board, and use brush and vacuum cleaner to clean the inverter circuit board and internal IGBT module, input and output reactor and other parts. The line board is dirty, using cotton cloth with alcohol or neutral chemicals.
(3) check whether the insulation of the internal wire in the inverter has the trace of corrosion overheating and discoloration or breakage, for example, it is found that it should be treated or replaced in time.
(4) the screw and other fastening components are generally loose because of the influence of vibration, temperature change and so on. All the screws should be fastened all over again.
(5) check the input and output reactor, transformer, etc. are not overheated, discoloring and burning or having odor.
(6) the inspection center DC circuit filter electrolytic capacitor small bump (safety valve) is not bulging out, the outer surface is not have cracks, leakage, swell and so on. General filter capacitor using a period of about 5 years, the longest period of inspection for a year, close to life, the best inspection period for half a year. The capacity of the capacitor can be measured by a digital capacitance meter. When the capacity falls below 80% of the rated capacity, it should be replaced.
(7) check the cooling fan work is not good, if the question should be replaced. Life is limited by the cooling fan bearing, according to work inverter needs 2-3 years to replace a fan or bearing. In the case of abnormal sound and abnormal vibration during inspection, it needs to be replaced.
(8) check whether the insulation resistance of inverter is in the normal range (all terminals and grounding terminals). Note that megaohmmeter can not be used to measure circuit boards, otherwise the electronic components of circuit boards will be damaged.
(9) disconnect the R, S, T terminals and the power supply cables of the inverter, and disconnect the U, V, W terminals and the motor end cables. The insulation resistance between each conductor and the conductor and the protection grounding of the cable is measured by megaohm.
(10) when the frequency converter is put into operation at the end of the repair, the motor should be run for a few minutes with the motor no-load test, and the rotation direction of the motor should be checked.