Some Important Compatibility Problems And Their Elimination In The Application Of Induction Motor With Variable Frequency Drive

It is very common to use Variable Frequency Drive (VFD) with Induction Motor (IM) in Industry due to its numerous advantages. The advance of power electronics technology has also facilitated mass utilization of this combination. However, the application of IM with VFD may affect the actual design, performance and reliability of IM. When small and medium size motors are improperly used with VFD’s, windings and bearings can fail prematurely. The Corona Inception Voltage (CIV), the voltage at which corona degradation begins in an insulation system is discussed, and the major factors contributing to the CIV of a motor’s insulation system are presented. The concept of shaft induced voltage (SIV) and its effect on bearings is also stated. The aim of this paper is to investigate the sources of the failures when motor and drive combination is set into practice and to discuss the possible remedies to eliminate them. In addition, harmonics, resonance and efficiency aspects related with VFD’s are also reviewed.