Why Variable Frequency Drives Cause Harmonic Distortion Variable frequency drives are widely used in modern factories. They control motor speed, improve process control, and make many systems more energy efficient. However, variable frequency drives also create harmonic distortion. The problem comes from the way variable frequency drives draw current from power supplies. They do not draw current i...
Capacitor Bank Failure Solution: When to Use SVG, AHF, or a Hybrid System Learn why capacitor banks fail under harmonic loads and when to use an SVG, AHF, or hybrid system for stable power factor and lower distortion. Harmonic currents can accelerate capacitor dielectric aging, increase transformer losses, and contribute to nuisance trips. At the same time, rapidly changing reactive ...
Three-Level AHF Stops Capacitor Failures in VFD Plants Capacitor banks can fail under VFD harmonic loads. Learn how a three-level active harmonic filter reduces THDi and supports capacitor-bank protection. A recurring VFD-plant problem looks like this: capacitor banks fail repeatedly even after replacement. The capacitors may not be the root cause. Nonlinear loads can inject 5...
Active Harmonic Filter Sizing: What Happens When You Get It Wrong Learn how harmonic current, load cycles, topology, temperature, and SVG/AHF selection affect THDi performance. Consider a textile mill with dozens of VFD-driven spinning frames. A 100 A active harmonic filter (AHF) is installed, but THDi at the PCC falls only from 28% to 19%. The unit is operating normally; it is simply too s...
The Hidden Costs of Incorrect Active Harmonic Filter Sizing Got a call last month from a panel builder in Malaysia. His customer — a textile mill running 47 VFD-driven spinning frames — had commissioned a 100A AHF three months earlier. THDi at the PCC dropped from 28% to 19%. Not terrible, but nowhere near what the spec promised. The supplier insisted the unit was working. It wa...