Determining losses of motors designed for converter operation

There exist no generally accepted methods to determine the losses and efficiency of motors designed for converter operation. There exist two alternative methods that are applicable to all motor technologies - the input-output method and the calorimetric method. In this paper, the both methods are used to determinate the losses of the standard 37 kW squirrel cage induction motor. The results obtained with these methods are further analyzed and the uncertainty of the methods are discussed.