A General and Accurate Approach to Stator Natural Frequencies Calculation Considering End Windings and Insulated Brackets

The accurate calculation of stator natural frequencies is crucial for predicting and mitigating vibration noise in motors. Traditional methods, such as the energy method, often simplify the stator structure by neglecting features like square slots and end windings, leading to inaccuracies, especially when these elements are significant and when stators include insulated brackets. In this study, we introduce a comprehensive and precise methodology for determining stator natural frequencies, accounting for the effects of square slots, insulated brackets, and end windings. The accuracy and efficacy of the proposed methodology were validated using a 9-slot, 6-pole motor stator, which demonstrated a maximum discrepancy of only 6.42% compared to experimental results. The universality of the method was further confirmed with a 12-slot, 8-pole motor stator. Additionally, using this methodology, we analyzed the motor's structural parameters, including stator yoke thickness, square slot depth, tooth width, tooth height, and axial length, to evaluate their influence on the natural frequencies. Our research provides practical insights for the design and optimization of motors to reduce vibration noise.