Selected elements of a new method of induction motor efficiency determination

This paper presents the results of estimating method of the energy consumed by induction motors and the legal situation concerning the efficiency of electrical motors in the European Union. Three elements of a new method of induction motor efficiency determination are described: methodology of taking into account the influence of non-sinusoidal voltage and the voltage unbalance on the motor efficiency and the application of the interval arithmetic in order to determine the border error of the induction motor efficiency. It is proved that the middle of efficiency interval for the direct method of efficiency determination is always equal to or higher than the measurement result and the radius of interval is longer than the border error.