A Faulty Paralleled CSI-Fed Induction Motor Drive: Practical Field Tests, Analysis and Problem Solving

Abstract

In this communication, a case study of practical field tests, analysis and problem solving of a faulty, paralleled current source inverter (CSI)-fed on induction motor drive is proposed. Since the induction motor and the drive system, which were installed and lasting over 10 years of operation in a cement kiln plant, was exposure to the problematic of abnormal temperature rising and having damaged cabling terminals. To tackle the problem, field testing data, evidence and diagnostic suggestion of the system was collected and analyzed. Key finding reveals that the paralleled CSI causes mismatching, phase-shifted, current flows into all three-phase stator windings, and thus consecutively resulting in excessive heat losses. As a result of data analysis, the corresponding method of problem solving has been taking into accounted. By tuning up the VFD's serial reactor, together with replacing and re-installing the new feeder cables and the induction motor after overhauled, respectively. The system is finally recoverable and ready to service with healthy conditions.