Prevention of Torsional Vibration in Fan Motor Shaft Systems with Multiblade Fans : 3rd Report: Method of Frequency Control using Correction Weights

Abstract

In order to avoid torsional resonance in a fan motor shaft system with multiblade fans and plural planes of symmetry perpendicular to the shaft, a method of frequency control using correction weights was devised. In this method, the vibration characteristics of a shaft system are controlled by using the natural frequencies of the system. A least squares method which uses the influence coefficients is used to calculate the size of the correction weights. This method was applied to the shaft systems with asymmetrical mass distribution, and its effectiveness was investigated in numerical simulations. It was found that a very marked effect of vibration suppression can be obtained if the planes of symmetry are considered when the correction planes are selected.