Monitoring of Leakage Flux for Rotor Fault Detection under non-adjacent broken rotor bars in Induction Motors

In this paper, leakage flux is monitored when induction motors expose to non-adjacent broken rotor bars fault. The detection of rotor faults based on stator current analysis may sometimes become challenging if the corresponding broken bar positions are in half and full pole-pitch. In such cases, electromagnetic distribution can be keep symmetrical due to induced magnetic field by corresponding broken bar positions. This leads to reduce diagnostics ability for rotor bar fault. In order to minimize the such problems, leakage flux is examined using finite element analysis (FEA) in induction motors. Comparative results for stator current and leakage flux are presented to show the diagnostics ability and advantages of leakage flux based analysis. The 2D-FEA results show that some characteristics signatures such as 3sf(s) and f(r)+sf(s) in leakage flux are more reliable signatures to detect broken rotor bar fault even the positions of broken bars are in half-and full pole pitch distance.