Converter-fed Induction Motor Efficiency Measurement under Variable Frequency/Load Points: An Extension of the IEC/TS 60034-2-3

As Variable Frequency Drives (VFDs) continue to dominate industrial process control, there is a need for stakeholders to quantify the converter-fed motor losses over a wide range of operating frequency and loading conditions. Although there is an increase in legislative activities, particularly in Europe, towards the classification and improvement of energy efficiency in electric drive systems, the handful of available standards for quantifying the harmonic losses are still undergoing validation. With regards to the IEC/TS 60034-2-3, which has been lauded as a step in the right direction, its limitation to rated motor frequency has been identified as one of its main weaknesses. Therefore, this study demonstrates how the IEC/TS 60034-2-3 methodology at norminal frequency can be extended over the constant-torque region of an induction motor (IM). The results presented in this paper provide good feedback to the relevant IEC standards committee as well as guidance to stakeholders.