Vibration Analysis on Variable Speed Machines

Stephen Bailey, Sr. Test Analyst, IVC Technologies


When it comes to Vibration Analysis as a means of Condition Monitoring, variable speed machines can offer many challenges to the analyst.  This presentation will consist of reviewing the various methods of monitoring / troubleshooting / diagnosing vibration analysis data for variable speed machines.  The topics outlined will include collection practices for conditiion monitoring programs on AC VFD motors, DC motors, turbines, and machines utilizing mechanical methods to vary the speeds.  Inherent pitfalls associated with performing vibration analysis as a function of CBM will be discussed, with sollutions for overcoming them.  Real world machines with actual vibration data will be used in these discussions, as well as validated case history information where applicable.

1. The inherent pitfalls that are associated with collecting / utilizing vibration data as a means of condition monitoring variable speed equipment.
2. How to overcome the obstacles associated with collecting / utilizing vibration data as a means of condition monitoring on variable speed equipment.
3. Recognizing condition based monitoring equipment limitations as they relate to variable speed equipment, while offering varied / non-standard technology based solutions.


I started working in Industrial Maintenance over 25 years ago. My career started as a multi-craft maintenance technician in building products facilities, which transitioned into Predictive Maintenance Technician work that included Vibration Analysis, Oil Analysis, IR Analysis, and Motor Current / Circuit Testing. In 2002 I began working for IVC Technologies as a Predictive Maintenance Technician, and am currently a Sr. Test Analyst in their Advanced Testing Group. As part of the Advanced Testing Group, I perform consulting services for all facets of industry. I have experiences in CBM / PdM Program audits, multi-channel vibration analysis testing, Operational Deflection Shape analysis, Experimental Modal analysis, force / torsional testing, online monitoring systems, and process analysis. These experiences have led to me having published articles in Uptime Magazine and AIST Magazine, with multiple speaking engagements at various conferences over the past few years.