Experimental investigation of conducted electromagnetic interference differential-mode performance in various split-phase induction motors designs

In industrial environments, motors in Variable Speed Drive (VSD) systems act as primary conduits for the propagation of conducted electromagnetic disturbances, including Differential Mode (DM). The Split-Phase Induction Motor (SPIM) is among the most widely used motors in ASD systems, making the analysis of its impedances and High-Frequency (HF) properties crucial for ensuring Electromagnetic Compatibility (EMC) and mitigating Electromagnetic Interference (EMI). Poor EMC management can result in malfunctions of nearby electronic devices.This article examines the DM current propagation paths in two motor types. The investigation aims to: (i) Identify the HF characteristics of these motors within the critical frequency range for conducted EMI (150 kHz – 30 MHz), (ii) Assess key EMC performance indicators, focusing on the windings of the main and auxiliary phases, and (iii) Compare the EMC performance of different SPIM designs through experimental analysis to select the most suitable motors for critical EMC applications. This approach not only addresses EMC challenges but also optimizes motor performance and ensures regulatory compliance in electrical systems where these motors play a crucial role.