High-Reliable Temperature Prediction Considering Stray Load Loss for Large Induction Machine

Temperature prediction for electrical machines is a crucial concern in order to increase power density and ensure satisfactory life span. For high-reliable thermal analysis, this paper addresses a versatile methodology to apportion the stray load loss (SLL) of the induction machine. The 2-D transient finite-element analysis has been performed to investigate electromagnetic losses. The calculated losses under the rated-load condition are superimposed with the experimental SLL. The synthesized losses are imported to thermal-flow analysis using 3-D incompressible steady computational fluid dynamics. Electromagnetic losses, winding temperature, and air flow rate are measured with the test of a 1.8 MW medium voltage motor, validating the overall analysis and the allocation of SLL.