Hello everyone, I am reaching out to see if anyone has encountered any issues with the MDX91A drives in their installations. We have a large setup with approximately 30 of these drives that have been running smoothly for the past 12-18 months. However, in June 2023, we experienced our first drive failure with a C0 fault related to the module bus issue. Despite setting all drives as masters and configuring the S3 switch correctly, the drives are exhibiting slave behavior due to a disconnection with the master. Recently, in March 2024, after a scheduled plant shutdown and restart, we have had 5 drives fail with the same C0 fault issue. These failures seem to be random across the installation, affecting only the SEW drives while other types, like Powerflex and Nord, remain unaffected. Some of the failed drives were even mounted and powered next to each other in the same panels. SEW has acknowledged the problem and provided replacement drives, albeit on a non-fault basis. Given the challenges faced during the COVID era in the supply chain, we suspect there may be a manufacturing issue causing these failures. Despite SEW claiming this to be an isolated incident, we are curious if others have encountered similar issues. Your insights would be greatly appreciated.
Update: Last week, SEW engineers replaced all the 'faulty' drives. These units were then sent to the service department in Germany for inspection, but surprisingly, no issues were found and they all functioned correctly once powered up. However, after a routine maintenance power down, two more drives experienced the same issue. Despite attempting a hardwired reset through the front IO terminals and a factory reset, the C0 fault persisted. We have now replaced the faulty drives with spares and successfully powered them up in a non-production machine. Currently awaiting a response from SEW.
We faced a very similar issue with an MDX91A drive last year. Like you, everything seemed okay initially, but then we started experiencing sporadic failures. SEW provided us with a replacement as well, nevertheless, the problem persisted. After some investigation, our team discovered that the issue had to do with the communication module rather than an actual fault with the drive. We resolved it by cleaning the module bus connectors thoroughly - there was some residual factory dust and dirt which seemed to interfere. It might be worth double checking the cleanliness of your bus connectors if you haven't done so already.
Hey there, we've been using MDX91A drives in several of our assemblies and experienced similar S3 switch configuration issues leading to a slave behavior. In our case, we found that it was not a manufacturing problem per se, but the drives were somehow more susceptible to power fluctuations and surges, which eventually led to the C0 fault issue. We initiated power conditioning measures, which seemed to have mitigated the problem to a certain extent. Also, we had a strict adherence to ambient operating conditions defined by SEW, that helped too. Not saying that it could be the same in your case, but just sharing our experience for what it's worth.
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Answer: The common issue being faced is a C0 fault related to the module bus problem, causing the drives to exhibit slave behavior instead of operating as masters.
Answer: The initial drive failure was experienced in June 2023, and after a scheduled plant shutdown and restart in March 2024, 5 more drives failed with the same C0 fault issue.
Answer: The drive failures seem to be localized to SEW drives only, with other types like Powerflex and Nord remaining unaffected.
Answer: SEW has acknowledged the problem and provided replacement drives, although on a non-fault basis. They claim it to be an isolated incident, but the users suspect a manufacturing issue may be causing the failures.
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