Transient thermal characteristics of induction machine rotor cage

Thermal analysis of an induction machine cage rotor during stall conditions forms an important part of design calculations. The study of rotor circuit thermal behavior is also useful to identify causes of failure in large cage rotor induction machines. The authors present a three-dimensional finite-element-based electrical-thermal analysis of the bar and end-ring area of a large rotor to examine its thermal characteristics during a stall. Details of temperature variations at key locations in the bar and end ring are provided. The calculations are compared to experimental results, and the advantages and limitations of the solution technique for rotor analysis are discussed