Electrical Testing

Tip of the Week: Power Quality, Part 1

Here are some common signs that you might be having problems with power quality.

How do you know if you have power quality problems?

The answer is you either conduct a battery of specific tests in the course of a power quality analysis, or you produce reports from your power quality monitor. Fully executing either approach requires expertise not typically present in plant engineering.

It might be better to ask how you know to suspect power quality problems. Here are some common signs, but note that their absence does not mean your power quality is necessarily what it should be:

•A high rate of motor bearing failures and/or motor winding failures.

•The mechanics find pitted bearings in mechanical drives and other equipment under their purvey.

•Circuit board replacement is a normal occurrence. Same for PLC module replacement.

•Lights flicker. Lights don’t seem bright enough. Lighting system component replacement is a normal occurrence.

•Neutral conductors appear discolored.

•Nuisance breaker trips occur, but their source is rarely, if ever, identified.

•Insulation resistance (IR) testing shows cable failure at an abnormal rate. Note that a qualified electrical testing firm can tell you from experience whether the rate is abnormal.

If you have any of these symptoms, suspect one or more power quality problems. You may be able to identify some issues with a little sleuthing and some basic measurements, but you’ll probably need a qualified firm to do a complete workup.

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