How Variable Frequency Drives Create Power Quality Problems Variable frequency drives (VFDs) are widely used in modern industrial systems because they improve motor control, reduce energy consumption, and increase production efficiency. However, as more facilities install VFD systems, VFD power quality problems are becoming a major concern. A variable frequency drive is a nonlinear load that chang...
A facility can operate normally on utility power and develop power quality problems after transferring to a standby generator. Drives trip, UPS systems report input faults and lights flicker—even though the load has not changed. Nonlinear loads are usually already generating harmonic current. The generator provides a weaker source, allowing the same current distortion to create greater volta...
Capacitor bank overheating after adding VFDs is a power quality symptom, not a capacitor defect. VFD rectifiers inject harmonic current, the bank offers a low-impedance path at those frequencies, and parallel resonance between the bank and the supply can amplify that current until fuses open, contactors chatter and capacitor cans swell. A capacitor bank supplies reactive power to correct power fac...