Mitsubishi inverter five fault analysis

1, OC1, OC3 failure. Mitsubishi inverter OC (overcurrent fault) is often caused by the following reasons (A500 series inverter is taken as an example). (1) Inadequate parameter setting problems, such as short time setting; (2) External factors, such as motor winding short-circuit, including (phase-to-phase short circuit, short circuit to ground, etc.); (3) Inverter hardware failure, such as Huo Sensor damage, IGBT module damage and so on.

In the current maintenance, we sometimes rule out the above reasons may not be able to solve the problem, OC failures still exist, of course, the replacement of the control board is not a solution to the problem, then you can consider whether there is a problem with the drive circuit. Mitsubishi A500 inverter detection circuit is very powerful, if any of these detection points have any problems, they may alarm and fail to operate normally. In addition to the drive power included in the general drive circuit, drive optocoupler isolation, drive signal amplification circuit, and output signal feedback circuit. In the case that the detection method introduced by us cannot solve the problem, we must pay special attention to whether the driving circuit is normal or not, and the detection direction mainly includes several components of the Mitsubishi driving circuit just introduced.

2, UVT failure. UVT undervoltage fault, I believe many customers will still encounter such problems in use, our common undervoltage detection point is the DC bus side voltage, after a large value of the resistance voltage divider sampling a low voltage value, and The standard voltage value is compared with the output voltage normal signal, overvoltage signal or undervoltage signal. For the Mitsubishi A500 series inverter voltage signal sampling value is obtained from the switching power supply side, and after optocoupler isolation, in our maintenance process, found that the damage of the optocoupler in the cause of the undervoltage fault in the very Large proportion, this phenomenon is still rare in the previous inverter maintenance.

3, E6, E7 failure. E6, E7 fault is not unfamiliar to the majority of users, this is a more common Mitsubishi inverter typical failures, of course, the causes of damage are many. (1) The integrated circuit 1302H02 is damaged. This is an integrated circuit that integrates the drive waveform conversion and multiplex detection signals in one IC. There are multiple signals associated with the CPU board. In many cases, problems with any signal on the IC can cause E6. , E7 alarm; (2) signal isolation optocoupler damage. In the IC IC 1302H02 and the CPU board between the strong and weak signals need to be isolated, the damage of the isolated optocoupler in the component damage ratio is still relatively high, so in the E6, E7 alarm, we must also consider Is it due to such factors; (3) The connector is damaged or the connector is not in good contact. Since the connection cable between the CPU board and the power supply board is broken after several times, it is prone to breakage, imaginary welding, etc. If the improper use is made on the plug side, the pin is prone to bending and breaking. Some of the above reasons may also cause the emergence of E6, E7 failures.

4, switching power supply damage. Switching power supply damage is also a common fault of A500 series inverters. Excluding the pulse transformer damage that we often mentioned before, switch FET damage, start-up resistor damage, rectifier diode damage and other factors, the common damage device is a piece of M51996 waveform generator chip, this is a control chip with on-off off time adjustment, output voltage regulation, voltage feedback adjustment and other protection in one. The areas where problems are more likely to occur are the 14-pin power supply, 7-pin voltage reference, 5-pin feedback detection, and 2-pin waveform output.

5. The power module is damaged. The damage of the power module mainly occurs in the E500 series inverter. For a low-power inverter, since it is an intelligent module that integrates the power device and the detection circuit, it can only be replaced when the module is damaged, but the maintenance cost is high and no maintenance value is available. For the 5.5KW and 7.5KW E500 series inverters, the 7MBR series PIM power modules are used. The replacement cost is relatively low, and some damage can be done to the inverters. In the history of nearly 85 years, Mitsubishi Electric has always been committed to the research and development activities of cutting-edge technology and expertise, and on this basis is engaged in the development and manufacturing of high-performance products and equipment systems.