The paper deals with the problems in the operation of non-linear loads, causing distortions in the sinewaves of voltages and currents. There is currently increasing use of variable frequency drives (frequency inverters) that drive electric motors and are such loads. The experimental results cover multiple measurements of voltages and currents harmonic components and the calculated values of the total harmonic distortion coefficients of voltage and current for each of the phases, supplying different loads. An analysis of the results obtained has been done and specific conclusions have been pointed out on the basis of the measurements carried out.
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