Energy balance of huge asynchronous machine during its run-up

To determine the temperature of the active parts (windings) of a real asynchronous machine under transient phenomena is a serious problem. Especially the temperature calculation of the bars of the squirrel cage rotor of the asynchronous machine may yield results which differ relatively largely from reality. In addition, if the precise measurement on the rotor bars is impossible due to absence of any sensors, the situation is unpleasant. This paper presents one possible method of how to take a rough estimate of the rotor bars temperature thanks to run-up measurement.