Fluke - Dirty power, can I have it and not know it?

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Equipment failures raise costs, while reducing revenue. The failure of one small component in a manufacturing process can idle an entire plant for hours, and poor power quality (aka “dirty power”) is a common cause of unplanned shutdowns and equipment failures. Just as clean water is essential for our health, so is clean power essential for the health of electrically- powered equipment - and the livelihoods that depend on that equipment. So what types of tests can you perform to determine if you have “clean” or “dirty” power?


First determine the loads in your plant or facility that are mission critical and are likely victims of dirty power. Controls for manufacturing processes, critical sensors, environmental controls and computer networks are some places to look. Obviously any load that could affect lifesafety or security should be considered critical.


Don’t rely on a simple voltage or current measurements to determine the quality of your power. It is important to check multiple aspects of the power system, including voltage quality, loading, harmonic content and grounding. The results of measurements should always be evaluated by an experienced electrician or engineer, especially if the results are ambiguous or confusing. Harmonics testing, for example, can produce confusing results and you may need to call in the experts. But being armed with the right measurements will help expedite the process and increase your confidence in your power system.


Perfect power at your service entrance doesn’t automatically mean clean power throughout your facility. In fact, most dirty power comes from within a particular building. Utility systems generally have a low source impedance that can overcome a lot of what consumers put back on the power grid. Overloaded circuits, undersized conductors, improper wiring, or improper grounding problems are very common causes of dirty power. Semiconductor switching in ASD’s, dimmers, or other electronic loads cause waveform distortion and may cause transients if the devices are improperly specified or start to fail. Problems can occur at the service entrance as well. Utilities switching power-factor correction capacitors can cause transient...



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