The main production line was revamped last year. One of the enhancements was putting all of the motors on variable speed drives under PLC control. This has sharply reduced mechanical problems, but all is not roses. The drives unexpectedly stop for no apparent reason; no amount of tweaking the settings has solved this. And the number of motor failures has gone up, instead of having gone down as anticipated.
What could the problem be traced back to?
It could be