Calculation and Analysis of 2-D Thermal Stress Field in Induction Motor with Compound Cage Rotor under Different Load

3kW two poles induction motor with compound cage rotor is illustrated in this paper, and 2-D thermal stress field of induction motor rotor is calculated and analyzed by finite element. Contrasting with common induction motor, induction motor with compound cage rotor has specific rotor shot shape and the bar is comprised of the upper compound material and the lower cast aluminium, which cause distribution of thermal stress is special. The motor with the rotor shot of compound material laid at single site is chosen to analyzing. The maximum thermal stress in the bar is calculated at different load, and the distribution of thermal stress in the bar is analyzed at rate load. The law of distribution of thermal stress in the bar has same reference value for designing new type of induction motor.