The plant has 18 productions lines. The electricians are responsible for the preventive maintenance on the controls, motors, and power distribution for each line.
The new plant engineer has asked why some of these lines have almost no failures and others need a repair ticket at least once a month. The lines are all similar, so it’s a good question. Nobody knows the answer, but the maintenance manager verified all the PMs are being completed on time, and the production superintendent verified all operators are properly qualified.
The plant engineer has tasked you with finding out why there is such a variance. Where should you start?
Are all the high and low failure rate lines on different feeders? If you have a high and low failure rate line on the same feeder, a power quality issue is not the common cause. Still, test for voltage imbalance, low power factor, and similar power quality issues.
Inspect the electrical system bonding on each line. Bonding deficiencies can mean undesired current is taking paths through equipment to get back to the source. Don’t rely on building steel or other indirect paths; the equipment grounding conductor needs to be the path.
Finally, look at who is doing the PMs on which equipment. You may find a correlation with failure rates; solve the training and procedure issues.