Even harmonic resonance-an unusual problem

This paper is a case study examining the cause, effect, and solution of an actual "noncharacteristic" even harmonic problem in an electrochemical plant. While issues concerning "characteristic" harmonics are well documented in the literature, limited information is available describing how noncharacteristic harmonic currents create operational problems. The author has not found any papers describing a case of even harmonic resonance and would like to share the experience of resolving a 4th harmonic resonance problem in the hopes it will benefit others.