What Is Vibration Analysis For Rotating Equipment Reliability Vibration analysis allows the maximum interval between repairs to be realized through monitoring the actual mechanical condition of a piece of rotating machinery. Equipment down time is not required for monitoring activities to occur. The monitoring, in turn, directly minimizes the number and cost of unscheduled machine outages created by component failures. Hence, optimum equipment availability may be obtained. Vibration Analysis is predicated on two basic facts: 1. All common failure modes have distinct vibration frequency components that can be isolated and identified. 2. The amplitude of each distinct vibration component will remain constant unless there is a change in the operating dynamics of the machinery. Monitoring the vibration from machinery can provide a direct correlation between the mechanical condition and recorded vibration data of each machine. Vibration analysis can be used to identify specific degrading machine components or failure modes of machinery before serious damage occurs. Typically, 80% of the machinery problems experienced can often be classified as either imbalance or misalignment. Imbalance and misalignment can lead to premature bearing, coupling, shaft seal, and gear wear. Most of the problems can be rectified by simply improving maintenance standards and procedures and by eliminating careless or sloppy work. Also, imbalance and misalignment do not only occur in established equipment over a period of time, they can be present after initial installation of a new piece of machinery. Vibration analysis can be used to validate that the new equipment has been properly installed. This would prevent the introduction of failure causes which would have a detrimental effect on the life of the equipment and the process which the equipment supports. It is important to note that the bearings in a machine-train are the primary limiting factor for operating life. The first indication of machinery problems often develops in the vibration signature of the machine's bearings. However, the bearings are typically not the cause of the problem. But since they are the weakest link in most machinery, the bearings are usually the first to fail. Vibration checks at points other than the bearings are also taken to check for structural problems. Experience has proven that on new or refurbished equipment, vibration data should be collected once a week for four consecutive weeks. This will enable a trend to be established for future comparison. The frequency of monitoring a piece of equipment after establishing an initial baseline is based on the following considerations:    • The machine's operating modes (i.e., intermittent or continuous speeds/loads).    • The machine's operating environment.    • The importance of the machine's function.    • Data derived from comparison of the initial baseline.    • Availability of spare parts. To regularly acquire enough data for complete diagnosis of a machine's potential failure would be "overkill" and unduly burden the data collection process. The periodic collection of vibration data on a prescribed route for trending purposes should be treated as a tool to indicate pending problems. Industry standards are utilized to determine a problem condition unless specific pieces of equipment dictate more stringent or lax alarm limits. Once a possible problem is identified, more data is collected from the equipment in order to aid the vibration analyst in determining the exact cause of the anomaly. In order to resolve the anomaly in an efficient manner, "if" and "what type" of information is needed. The questions asked are:    • What is the problem?    • What is the machine's history? What has the operator observed?    • When did the problem start? Was it sudden or gradual? Did the machine ever run properly?    • Have any changes been made recently? Modifications? Realignments? Changes in machine speed? Click on image for larger image Click for larger image Click for larger image Click for larger image