Hitachi inverter common faults and solutions - Database & Sql Blog Articles

Crystal oscillator

3225 50M crystal

Photocoupler

In the long-term maintenance of Hitachi inverter work, the summary is provided for the inverter maintenance and operation personnel to learn.
1. LCD display In the early days, the Hitachi inverter that we often encounter in the domestic market is the HFC-VWS3 series. This is a V/F controlled inverter. The power module uses GTR's high power transistor. Its maximum power can be 132kW, and it is displayed by liquid crystal panel. This is still a high grade in the Japanese inverter in the same period. However, compared with the frequency converter displayed by the digital tube, the service life and stability of the liquid crystal are relatively poor. We often encounter the brightness of the liquid crystal display but no subtitles. This kind of situation is mostly due to the driving power supply side of the liquid crystal display. The replacement of such capacitors can solve the problem caused by the decrease in the capacity of the chip ceramic capacitors.
2. Switching power supply In addition, a large number of thick-film circuits are used in this series of inverters, including thick-film circuits for switching power supplies and thick-film circuits for driving parts. The use of thick film circuits is mostly due to technical considerations. When encountering similar problems, the first thing we should consider is how to judge the quality of these thick-film circuits. For the maintenance of the inverter, how to find out the fault is also an important task. For the damage of the switching power supply, if the peripheral components are excluded. Including the damage of the switch tube, the starting resistor, the pulse transformer, etc., the most likely problem is the thick-film drive circuit of the switching power supply. Without obvious damage, we can add the DC voltage to test whether the thick-film circuit can output normally. The driving waveform, the applied DC voltage is generally around 15V. If the output waveform is normal, we can generally assume that this thick film circuit is normal. The non-waveform output can basically judge that the thick film is damaged, and replace the thick film to solve the malfunction. The thick film circuit of the HFC-VWS3 series inverter is also prone to failure, but since all components on the thick film circuit have been packaged, maintenance is relatively difficult.
3. E9 alarm In J300 series inverter, we often encounter E9 alarm. We can check the three-phase input side power supply. J300 inverter has three-phase input voltage detection, and the input voltage is sent to the CPU through the voltage divider resistor. E9 alarms may occur in the absence of phase and input voltage is too low.
4. Faults These faults generally occur when the inverter is powered on. Generally, this fault is not a pure hardware damage, but it is often encountered. The focus of our inspection can be placed on some connectors, including The operation panel is connected to the inverter, and the control board is connected to the drive board. In addition, such faults can occur in the DC side undervoltage.
5. E30 IGBT failure
A fault phenomenon that SJ300 series inverters will encounter is the E30 alarm. There are several possibilities for the E30 alarm: the power module is mainly damaged. The SJ300 series inverter uses the PIM module produced by Fuji, Japan. The rectifier and inverter are integrated modules, and the IPM is intelligent with the J300. The module is different. Of course, damage to the module will cause the E30 alarm to appear. However, there are also many cases where the PIM module is not damaged, but a fault occurs on the detection of the upper bridge drive circuit. The fault signal is isolated by the optocoupler and transmitted to the alarm output of the main control board.