Abstract: Temperature rise in an electric motor can significantly impact its operational performance and safety, making it a critical concern in motor design optimization. In order to analyze the temperature rise trend of a 30 kV·A air-cooled brushless synchronous generator's armature winding, a fluid-structure coupled model of the generator is established based on the principles of fluid mechanics and heat transfer. Taking into account the tolerance of winding resistance errors, a step-by-step iterative method is proposed to correct the copper losses in the winding. The iteration process continues until the specified time is reached, and transient temperature results are obtained for error tolerances of 2%, 5%, and 8%. Furthermore, the highest temperature curve of the armature winding is fitted under the assumption of zero error tolerance. Experimental temperature tests are conducted at ambient temperature to validate the simulation results, providing a method for predicting the temperature rise trend of the winding.