Paper No. 99
By Troy Feese
Published by Uptime Magazine, June/July 2011
This article provides a case history of a forces draft (FD) fan that experienced high vibration due to unbalance and an impeller resonance near the operating speed. The common balancing method of influence coefficients was unsuccessful due to varying phase data. However, vibration was reduced to an acceptable level using the four-run method without phase data.