Siemens inverter V20 series alarm OC ** maintenance ideas.
The OC alarm is the OC alarm with more faults in the Siemens inverter, so this time I would like to share the fault analysis, detection and maintenance ideas of the OC alarm of the Siemens inverter.
1) The reason why the Siemens inverter reported OC failure.
In fact, many brands of inverters will have OC fault alarms, they all have the same fault name called overcurrent fault, overcurrent fault is very common in maintenance, especially in this maintenance of a batch of Siemens inverter overcurrent fault is very common, overcurrent fault factors are more, so it is likely to be with the characteristics of the factory and the operation Xi of workers. OC alarms need to have a normal understanding. It is an instantaneous model that can also be explained by instantaneous overcurrent, so when this fault occurs, it brings difficulty to our detection, and if the instantaneous current exceeds 200%, the inverter will judge the overcurrent fault, and the inverter will open self-protection. There are many factors that occur in overcurrent faults, and multiple faults need to be detected and eliminated together.
2) What are the factors that cause Siemens inverter to report OC failure?
According to the practical experience of multiple inverter maintenance, it is found that there are mainly the following factors that cause OC alarm overcurrent faults: detection circuit faults, faults caused by strong current interference, alarms caused by drive IC and IGBT faults, poor contact between MCU motherboard and power supply driver board connection cables or terminals, and a fault that we generally do not encounter is the DC loop energy storage capacitor or poor contact will also cause OC inverter failure.
There are so many reasons that can cause overcurrent faults, so overcurrent faults are a comprehensive fault. Among them, the two common ones are overcurrent caused by circuit faults and faults caused by IGBTs, and we can focus on line detection of these two modules to quickly troubleshoot the faults. Siemens' drive IC or external power device has poor contact, and the driving ability becomes worse after being used for too long, which makes the IGBT under-excitation on-resistance become larger and generate overcurrentSecondly, the IGBT module fails, which is due to many reasons, such as overheating damage and strong current breakdown, which may lead to the failure, which makes the IGBT falsely report the overcurrent to the CPU.
Another important cause of failure is a failure of the current transformer, i.e. the detection circuit. The specific test method is to use an AC current generator to send a rated current signal to the transformer, and test the output AC voltage or waveform at the OUT end, so that you can detect whether the fault of the detector circuit transformer is faulty, and if so, replace the corresponding module to solve the problem.