Noise and vibration from induction machines fed from harmonic sources

Electrical machines are increasingly being fed from supplies containing significant harmonic content. This is true both in conventional systems where harmonic levels are steadily increasing and in variable speed drive voltage-source inverters which are being used in ever greater numbers. This paper examines how the noise and vibration level of machines is affected by increased levels of distortion and also how the vibration is affected by machine loading. The methods described apply to a wide range of machine applications