Overview of Condition Monitoring Methods with Emphasis on Industrial Fans

Abstract

In any industrial fan, the rotating elements are located within some form of bearing arrangement. Defects, such as unbalance, will lead to an increase in vibration which is transmitted via these elements to the fan supports. As the bearings wear or as impeller balance deteriorates due to the effects of erosion, corrosion or dust build-up, there will be a corresponding increase in vibration magnitude. The rate of change of amplitude is a useful indication of the fan's ‘health’. The paper considers the fundamental equation of vibration and the disturbing forces involved. It is shown that a baseline fan signature is necessary if maximum benefits are to be achieved by any fan health programme. Ultimately, well-designed and installed bearings will fail due to fatigue. The concept of L10 life is also introduced and some of the methods for predicting the onset of failure are described.