Motion amplification: a new tool for vibration diagnosis

Conventional vibration analysis

For conventional vibration analysis, accelerometers must be used to acquire the necessary data. An accelerometer must be installed for each measurement point. When a simultaneous recording of several points is needed, a data acquisition system must also be used.

Moreover, since the analysis of such a large quantity of data is based on complex techniques (FFT, modal analysis, etc.), an expert must interpret the results and render them into non-technical language before they are communicated to the relevant people.

Since each accelerometer measures vibrations at a specific location on the equipment, the data collected may sometimes be insufficient. Also, this may not become apparent until the experts analyze the data. Additional measurements would then need to be taken, which could turn out to be a complex procedure.

Safe access must be ensured when placing measuring instruments on the equipment to be monitored. For example, to prevent exposure to moving parts, it may be necessary to stop production or to install a means for overhead access or for protection against falls.

Motion amplification

Developed by RDI Technologies, motion amplification technology uses a high-speed camera to produce a video of the machinery being monitored, such as a pump in operation. The analysis software turns each pixel into an accelerometer and provides an enormous number of measuring points. As it is possible to see the amplified movement in real time, a preliminary analysis can be carried out in the field. This makes it possible to confirm on site that all the necessary data has been recorded. In certain cases, the cause of the problems can even be determined on site, without requiring further analysis.

One of the key advantages of this technology is that the results can be seen and therefore understood by everyone. Machinery can be monitored as a whole (a pump with its motor) and causes of problems being investigated can be determined more easily. The analysis software displays the motion vectors, thereby highlighting the vibration modes. In addition, it is possible to see the amplified movements in a form similar to a heat map (with colours), making the various vibrations even clearer.

Since data acquisition is non-contact, there is no need to shut down equipment or install a means of special access if the object being monitored is visible from a secure location.

Motion amplification can also be used to monitor structural cracks as well as pipe resonance and vibration, or to take measurements that are not possible with conventional accelerometers.

To watch some examples or learn more about motion amplification, refer to the RDI Technologies YouTube channel.

It is important to note that motion amplification is efficient at low frequencies because the vibrations are greater at those frequencies. The specialized camera is designed to capture low-frequency vibrations, whereas with accelerometers, the signal must be converted into motion to offer similar results. While it does not replace the tools for conventional monitoring routes for monitoring bearings requiring high-frequency detection, this technology is a complementary tool specialized in low frequencies for structural, foundation or resonance interpretation issues.

In summary, motion amplification:

• complements conventional vibration analysis and is recommended for monitoring low-frequency vibrations.
• makes it possible to analyze and see complex phenomena (modal analysis) quickly and on site.
• offers a safety advantage (non-contact measurements).

BBA is a service provider authorized by RDI Technologies in Québec. For more information, contact us!