Suppose a piece of production equipment is down. You open the controls cabinet to be greeted by the unmistakable smell of burnt semiconductors. You replace the toasted circuit board and voilà — the machine starts and runs properly. While you exchange high fives with the operator, another downtime call comes in. Off you go to solve yet another downtime issue. But did you really solve this one?
You could assume that the board was destroyed by some kind of spike that came in through the service entrance. This is a bad assumption, because most power quality events (and chronic power problems) originate inside a facility. To complete this repair, you must go through a methodical investigative process to identify the source of that power quality problem. The process may not identify this particular problem, but skipping it means you definitely won't identify the problem.
Using this procedure, you’ll probably be able to identify and correct the reason the circuit board became toast. Your alternative is to keep replacing circuit boards while explaining to incredulous managers that these things "just happen."
Here's a fact that will help you figure out your first steps: Most power quality problems damage equipment because of violations of the NEC, specifically Chapter 3 and Art. 250, Part V.
In subsequent issues, we'll discuss what those violations are. Beyond those violations are the other causes of semiconductor destruction, and we'll discuss the cures.