Deformation and Fracture Behavior of Stator Windings Subjected to Cyclic Bending Loading

This paper presents the deformation and fracture behavior of stator windings under cyclic bending loading. In this study, two different kinds of stator windings, which are impregnated with epoxy and polyester resins, are examined. The flexural stiffness and tanδ characteristics of the stator windings are measured, applying cyclic loading to the stator nd-windings of up to 107 load cycles. Their variations are revealed under various strain amplitudes, and the failure mechanism of the stator windings under cyclic loading is discussed. The breakdown voltage is also measured in the last stage of each test, and the correlation between the reduction rates in the breakdown own voltage and the flexural stiffness is clarified. The failure criterion on the mechanical strength of the stator windings under cyclic loading is proposed.