Electrical Troubleshooting Quiz

Your plant engineer retired last year. Her replacement is eager to add some bullet points to his résumé. The new plant engineer is a mechanical engineer, but thinks he also knows electrical systems.

As you're walking past a conference room, he calls for you to come inside. He then introduces you to a salesman you've never met. The salesman isn't affiliated with your electrical distributor or any of your vendors. He's pitching a harmonics mitigation system. He shows you a scary-looking harmonics readout and says, "We're going to solve this problem."

How can you verify whether there really is a problem that needs solving?

Take the plant engineer aside and explain that harmonics are normal. The readout might not indicate anything worth solving, and further investigation is warranted to prevent making a costly mistake.

Four kinds of analysis will help you make a correct decision:

  • Harmonics analysis: A qualified person analyzes the harmonics signature, looking for things like a large third harmonic. Readings must be taken on individual feeders and branch circuits.
  • Thermographic analysis: If harmonics are outside acceptable limits, they will cause overheating of conductors and connections. A qualified thermographer can determine the severity by analyzing thermographic readings.
  • Power analysis: A handheld power meter can provide lots of information. Use one to look at the quality of the 60Hz waveform. If you don't see notches, clipping, and other severe distortion, it's likely the harmonics are not adversely affecting equipment.
  • Failure analysis: Look at repair logs to see if there's a power quality issue.
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