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International Journal of Rotating Machinery
Volume 2010, Article ID 962804, 12 pages
Research Article

Condition Monitoring of Forward Curved Centrifugal Blower Using Coast Down Time Analysis

1Department of Mechanical & Industrial Engineering, Caledonian College of Engineering, P.O. Box 2322, CPO 111 Seeb, Oman
2Advisor to Chancellor, VIT University, Vellore, Tamil Nadu 632 014, India
3Associate Dean (PGS and R), Caledonian College of Engineering, P.O. Box 2322, CPO 111 Seeb, Oman

Received 19 April 2010; Accepted 17 August 2010

Academic Editor: R. Amano

Copyright © 2010 G. R. Rameshkumar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Mechanical malfunctions such as, rotor unbalance and shaft misalignment are the most common causes of vibration in rotating machineries. Vibration is the most widely used parameter to monitor and asses the machine health condition. In this work, the Coast Down Time (CDT), which is an indicator of faults, is used to assess the condition of the rotating machine as a condition monitoring parameter. CDT is the total time taken by the system to dissipate the momentum acquired during sustained operation. Extensive experiments were conducted on Forward Curved Centrifugal Blower Test Rig at selected cutoff speeds for several combinations of combined horizontal and vertical parallel misalignment, combined parallel and angular misalignment, as well as for various unbalance conditions. As mechanical faults increase, a drastic decrease in CDT is found and this is represented as CDT reduction percentage. A specific correlation between the CDT reduction percentage, level of mechanical faults, and rotational cutoff speeds is observed. The results are analyzed and compared with vibration analysis for potential use of CDT as one of the condition monitoring parameter.