Investigation of Stator Windings Looseness of Polyphase Induction Machine after Rewinded in Workshop: Numerical and Experimental Analysis

Electric machines, particularly induction motors, are widely used in industry as they are robust in construction and require less maintenance. These machines are continuously operated under high loading conditions, which may result in machine vibrations. The Experimental-Modal-Analysis (EMA) technique is employed in this research to determine electrical machine vibrations. The hammer test is a popular EMA approach for locating the exact location of winding looseness. EMA test is executed on the stator winding to extract the modal parameters to find exact deformation in machine windings. Mathematical calculations and a numerical model are developed to validate the experimental data. The EMA’s Operational Deformation Structure (ODS) validates the winding’s looseness precisely. Two test machines’ MA and MB windings are tested with EMA to evaluate the stator slot structure’s looseness. Finally, the proposed technique is compared with the finite element technique along with mathematical calculations for verification.