FREE copy of the Uptime Elements Implementation Guide once you subscribe to Reliability Weekly

Collecting proper bump test data can often feel like an art form rather than being a true science. Lots of information has to be set up before acquisition, resulting in messages such as "signal overload" and "waiting on trigger" etc. Parameters such as window type, trigger type, and % pre trigger all have to set up in advance. The process can be quite time consuming and frustrating for an inexperienced analyst.

This maintenance tip provides an easier and faster means to capture these important data. We often use the time waveform function to collect transient vibration measurements, where cracked shafts and gears and resonances are being investigated. If a potential resonance condition is suspected, you just need to collect long time waveform data, bumping the machine every five seconds or so. Collection is typically accomplished in less than a minute. By using the partial waveform analysis feature available in most PdM software packages, you can then pan and zoom collected time waveform data and pinpoint natural frequencies that could lead to a resonance condition.

Waiting for triggers and experiencing signal overloading and other warnings are eliminated in using this simple data collection method. The results using time waveform are fast and accurateand involve no guesswork.

Users of this technique say that it is similar to the old method of taking a movie and capturing frame-by-frame snapshots of the desired data.

A screen shot of captured long time waveform data over a 20-second interval is shown below.

commtest fig 1

commtest fig 2

In selecting just one good ring-down effect of the bump in time and converting it to frequency will pinpoint the natural frequency, 765 CPM in this case.

Tip Provided by: Dennis Shreve, CMRP - Customer Support Engineer
Commtest, Inc.
Tel: +1 865.588.2946
Commtest Logo

Upcoming Events

August 8 - August 10, 2023

Maximo World 2023

View all Events
80% of newsletter subscribers report finding something used to improve their jobs on a regular basis.
Subscribers get exclusive content. Just released...MRO Best Practices Special Report - a $399 value!
Internet of Things Vendors Disrupting the Asset Condition Management Domain at IMC-2022

Internet of Things Vendors Disrupting the Asset Condition Management Domain at IMC-2022 The 36th International Maintenance Conference collocated with the RELIABILITY 4.0 Digital Transformation Conference [East]

Asset Management Technology

The aim of the Asset Management technology domain is to assure that IT/OT systems are focused on creating the value from the assets and that the business can deliver to achieve organizational objectives as informed by risk.


TRIRIGAWORLD AWARDS honors excellence in space optimization and facility management, A event to further advance asset management

IMC-2022 Who's Who: The World's Best Run Companies

The International Maintenance Conference (IMC) provides a fresh, positive community-based curated experience to gain knowledge and a positive perspective for advancing reliability and asset management through people, their managers, the strategy, the processes, the data and the technology. The world’s best-run companies are connecting the workforce, management, assets and data to automate asset knowledge that can be leveraged for huge beneficial decisions.

Uptime Elements Root Cause Analysis

Root Cause Analysis is a problem solving method. Professionals who are competent in Root Cause Analysis for problem solving are in high demand.

Reliability Risk Meter

The asset is not concerned with the management decision. The asset responds to physics

Why Reliability Leadership?

If you do not manage reliability culture, it manages you, and you may not even be aware of the extent to which this is happening!

Asset Condition Management versus Asset Health Index

Confusion abounds in language. Have you thought through the constraints of using the language of Asset Health?

Seven Chakras of Asset Management by Terrence O'Hanlon

The seven major asset management chakras run cross-functionally from the specification and design of assets through the asset lifecycle to the decommissioning and disposal of the asset connected through technology

Reliability Leader Fluid Cleanliness Pledge

Fluid Cleanliness is a Reliability Achievement Strategy as well as an asset life extension strategy