Your electrical services company just landed a new client, one seeking to solve excessive downtime. A thermographic survey revealed many suspect connections. Further investigation found most were indeed bad, with the primary failure mode being corrosion. There is also corrosion evident on enclosures and other metal surfaces.
The plant doesn’t have any wet processes. Their manufacturing process involves making extruding plastic from dry resin pellets to make some components. They assemble those with purchased components to produce finished goods.
Corrosion isn’t limited to hinges and scratches where paint has been inadvertently removed. Corrosion is bubbling under the paint. Several motors exhibit corrosion, though you’ve never seen it on the same models in other plants.
How might you solve this?
First, examine the corroding enclosures and motor cases for proper bonding. If stray current is being generated but does not have a low impedance path to the source, it will travel through all the other (higher impedance) paths presented to it.
Carefully examine the “ground” connections at the extruder power supplies. Is there a low-impedance “ground” path back to the source? Test the extruder heating elements; replace any bad ones.
Does the plant have a mix of copper and aluminum conductors in its power distribution system? What about ground rods? Putting copper and aluminum together basically creates a corrosion-producing battery. After correcting errors, consider recommending a cathodic protection system.