Power, magnetic and ground harmonics have a negative impact on the reliability of your electric motors both electrically and mechanically. We often focus just on the power harmonics when reviewing information on power quality, but rarely view the self-generated electric machine harmonics and the harmonic content present in grounds and neutrals. Over the past several years I’ve become more aware of the non-power harmonic issues as the problems we have identified that are tied directly to ground, neutral and machine slot harmonics are on the rise. We often see these issues in terms of: problems with ‘nuisance tripping’ of protective devices; the rapidly increasing number of bearing defects that appear as electrical discharge, even when a machine is operating across the line; failure of electronic systems; insulation defects and power electronic failures; increased lightbulb replacements; and, even a lack of savings following the installation of energy savings devices.
For this brief overview of the harmonic impact on electric machine reliability we will first break up each type of harmonic issue and then will discuss real-world impacts from our field work and fault investigations.
Evaluation-of-the-Impact-of-Harmonics-on-Electric-Machines