Abstract: Under the rated load conditions,the rotor temperature is high and the thermal stress distribution in all directions is not even,which will affect directly the service life of the motor and is one of the main causes of the broken bars fault.This paper deals with 3-D temperature estimation for the squirrel-cage induction motor of Y802-2.The 3-D temperature model of the induction motor is established,and it employs finite-element method to analyze the thermal fields.The theoretical predictions are verified by direct comparison with experimental results.Research found that the heat flux located at the joint of the rotor bar and the end-ring is rather high,indicating that the position often fracture,which is consistent with the reality.