Motor Efficiency Determination of SynRM and Measurement Uncertainty

Electric motors are one of the largest electricity usage in the world. It is estimated that they consume between 43% and 46% of global electricity consumption. Recent studies show that efficiency values of Synchronous reluctance motors (SynRMs) reach IE5 Ultra-Premium Efficiency Class. The experimental determination of SynRM efficiency is getting more and more important, because of the need to place these motors in the right energy efficiency levels defined by international regulations. According to IEC 60034-2-3 standard, the efficiency of SynRM is determined by applying the direct or indirect efficiency similar to converter-fed AC induction motors. In this paper, a comparative analysis between direct and indirect efficiency determination for 75 kW SynRM, according to IEC 60034-2-3 standard is proposed. Measurement uncertainty analysis of the direct efficiency determination is carried out from the accuracy requirements for measurement equipment, as required by the GUM and IEC standard.