Calculation and Optimization of Thermal Stress in Induction Motor with Double-Skewed Rotor

Double-skewed motor with intermediate ring (IR) is often utilized to reduce the electromagnetic noise. However, the IR in the middle of rotor also brings the extra thermal faults. To avoid the potential rotor bar broken caused by thermal stress, a new IR model is proposed for the double-skewed rotor induction motor in this paper. The thermal stress distribution is calculated by the electromagnetic field coupled with the thermal stress field, and the potential bar fracture point caused by maximum thermal stress is found. Then, the new rotor model thermal stress distribution is calculated compared with a conventional IR, verifying the changed thermal. In addition, the thermal stress field distribution of the new model is more reasonable. Then, the difference of leakage reactance of the new model and conventional IR is analyzed. In conclusion, New trapezoid cross-section IR is able to improve motor starting performance, this method analyzed and validated by Finite Element Method (FEM).