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Power Transmission Distributors Association is...

the leading association for the power transmission/motion control industrial distribution channel, bringing together distributors and manufacturers.

Resources | Product Training | PT/MC Tech Tips | Vibration Analysis

Tech Tip: Vibration Analysis

Enhance your employees’ product and industry knowledge with PTDA’s Tech Tips. This library of online tips, hints and techniques may be used to educate new and current employees on power transmission/motion control (PT/MC) products, technologies and concepts and serve as reference and reminder for more experienced staff. Tech Tips are based on the expertise of PTDA member companies, content from Motion Control Made Simple or PTDA’s Power Transmission Handbook®, the definitive resource and training tool on PT/MC products.

Visit the full library of Tech Tips for additional products.

Understanding Vibration Analysis

Three tips to make vibration analysis easier:
  • Bearing fault frequencies are a function of the bearing geometry (rolling element diameter, number of rolling elements, contact angle, etc...) so bearings with the same geometries will have the same frequency coefficients no matter what other differences make up the bearings (e.g., differences in materials, clearance class, precision class).  
  • Most problems with rotating machinery, such as unbalance or misalignment, are synchronous to the running speed, thus they have peaks that occur at whole number multiples of the running speed (e.g. if running speed is 500 rpm and you have a peak at 1500, then that is an whole number multiple of 3 times the rpm).
  • Bearing problems are non-synchronous and thus will never have a peak at an whole number multiple of the running speed (e.g., if running speed is 500 rpm and you have a peak at 165 then that is a multiple of 0.33 and could be a fundamental train frequency defect for the bearing).
Since vibration analysis is complicated, the most effective way to use it is to take repeat measurements at regular intervals and look for changes so you can catch problems early.

The information provided in Tech Tips is not meant to be all-encompassing, but rather to draw attention to and provide information about the particular subjects covered.  All suggestions and recommendations contained in Tech Tips are based upon information that is believed to be accurate to the best of the experience and knowledge of PTDA's contributing members, but are made without guarantee or representation as to results.  PTDA and Tech Tip contributors expressly disclaim any warranties or guaranties, express or implied, as to the accuracy or completeness of any information published in Tech Tips, and disclaims and makes no warranty that the information in Tech Tips will fulfill any of your particular purposes or needs.  PTDA and Tech Tip contributors disclaim liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on Tech Tips.