Most motors in your plant are under automatic monitoring for vibration and temperature. In one area, the motors keep setting off their temperature alarms. Motor failure rates there are higher than in other areas of the plant.
The Plant Engineer told you voltage imbalance isn’t an issue, “…because it’s only 2.6% and you’re allowed 3%.” He’s looked into the cooling provided to the motors. As a test, the mechanical techs built a sheet metal hood for one motor and ducted forced air to