Influence of voltage subharmonics on induction motors of various efficiency classes

Power quality disturbances related to voltage waveform distortions and effective value deviation are common in power systems. Apart from higher harmonics, subharmonics and interharmonics may also appear in voltage waveforms. The presence of the above-mentioned disturbances causes additional power losses and an increase in thermal loads on induction motors. In this paper, the results of the study of the influence of subharmonics present in voltage waveform on the currents in the investigated induction motors of standard efficiency class – IE1 and high efficiency class – IE3, are presented.