Alternative methods for electric machine rated load temperature tests

The rated load temperature rise of an electric machine is an important performance metric that is typically determined by loading the machine at full load. However, it takes several hours to complete as the final temperature of the machine is only known after the machine is thermally stable. It would be desirable to complete such a test in 'minutes' instead of several hours. For large machines, it is practically impossible to load the machines at full load, due to lack of dynamometer capacity. It is therefore desirable if such a test could be performed without running the machine at full load. This paper proposes to determine the rated load temperature of a machine in a rapid manner. Two methods are considered: (i) short time overloading of the machine and (ii) a superposition equivalent loading approach that allows for determining the temperature rise of the machine without testing it at full load conditions. The obtained results indicate that these methods can be applied with suggested improvements to determine temperature for both small and large machines.