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Power Quality: What and Why?

Noah Bethel | Vice President-Product Development, PdMA Corporation

Power Quality: What and Why?

Power Quality = Voltage Quality

Voltage quality can be degraded in several ways. You can have high or low voltage in reference to the motor nameplate, including transient spikes of voltage. There can be imbalanced voltage between the three phases. You also may experience voltage with a high harmonic content driven by non-linear loads such as lighting, computers, and VFDs. All of these conditions can negatively affect motor performance through increased heat and vibration and insulation breakdown. IEEE-519 and NEMA MG1 address these conditions and suggest de-rating your electric motors to account for the poor voltage quality. No calculations are required on your part; the PdMA software calculates the de-ratings for you, letting you know what you can expect from your electric motors.

To see the six-channel In-Rush/Start-Up test used to identify a power quality issue on a servo motor drive, go to our collection of PdMA case studies at and click on the “Rogue Robots” case study.

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About the Author

Noah Bethel Vice President-Product Development, PdMA Corporation

Noah has over twenty-five years of broad operations and electrical systems maintenance experience in industrial, commercial, and military settings ranging from nuclear submarines to world class amusement parks. His experience includes high and low voltage, AC and DC, power generation, power distribution, motors, and motor controllers. Noah is currently in charge of product development for new and existing PdM technology at PdMA Corporation.

Noah is a graduate of the University of the State of New York and the Naval Nuclear Power School and Training Unit. He is a Certified Maintenance Reliability Professional, with field experience in motor circuit analysis, current signature, power analysis, thermography, vibration analysis, oil analysis and ultrasonic testing.