Vibration analysis is a time-tested method for evaluating the health of industrial machinery, including electric motors. It helps determine whether a motor is operating efficiently or if it might require motor rewinding in Singapore or other corrective measures. By comparing recorded vibration measurements to the motor’s “normal” vibration signature, technicians can assess its condition. This approach can be used for both corrective and predictive maintenance, with the latter offering the significant advantage of forecasting potential issues based on trends in the motor’s behaviour over time.
However, motors only benefit from vibration analysis when the process is executed properly. Mistakes during the process can lead to inaccurate readings, rendering the analysis useless and potentially leaving equipment vulnerabilities undetected. To get the most out of vibration analysis, avoid these six critical missteps:
1. Testing the Wrong Motors
If you are testing the wrong motors, you are wasting time and resources. The motors that should be prioritised for vibration analysis are the ones deemed critical to your operations. This is where performing a criticality analysis becomes indispensable. By assigning a risk rating to each motor based on its importance and potential impact on your processes, you can determine which assets warrant close monitoring. Skipping this step may leave your most vital equipment unchecked.
2. Lacking In-Depth Knowledge of Your Machinery
Even the best tools for vibration analysis are ineffective if the technician doesn’t fully understand the equipment being tested. Comprehensive knowledge of the motor is essential for obtaining accurate readings and interpreting the data effectively.
Details like the number of teeth in the gears, the shaft’s running speed, and the motor’s overall design all influence its vibration signature. Without this insight, you risk placing sensors incorrectly or misinterpreting the data collected. A deep understanding of your machines not only ensures accurate data collection but also allows you to make sense of the results and act on them appropriately.
3. Ignoring the Motor’s Actual Speed During Data Collection
Using the motor’s nameplate speed as a reference for vibration analysis is a rookie mistake. The nameplate speed represents the manufacturer’s design specifications, not the motor’s actual operating speed, which often varies in real-world conditions.
For example, the actual speed of an induction motor will always be slightly lower than its synchronous speed due to slip. Motors driven by inverters may operate even further below their nameplate speed. To ensure the accuracy of your analysis, always record the motor’s actual speed at the time of data collection.
4. Collecting Incomplete Data
Vibration analysis isn’t a one-and-done activity—it requires thorough data collection to provide meaningful insights. This involves capturing a full-spectrum vibration signature across the axial, vertical, and horizontal axes at four critical locations: both ends of the motor and both ends of the driven equipment.
Unfortunately, busy maintenance schedules often lead to shortcuts, such as taking a single reading on one axis. This can completely undermine the effectiveness of vibration analysis, as certain fault indicators only appear on specific axes. Without a comprehensive dataset, you risk missing early signs of failure, leaving your equipment vulnerable to avoidable breakdowns.
5. Overlooking the Limitations of Your Equipment
While vibration analysis equipment continues to improve, it still has limitations that analysts must account for. For instance, standard sensors are often blind to extremely high or low frequencies unless specialised sensors are used. Additionally, vibration analysis cannot reliably assess lubricant conditions—a common misconception.
It’s also important to note that upgrading to the latest and most advanced equipment can yield unexpected results. A sudden peak on a graph, for example, might not indicate a new issue but rather the equipment’s improved sensitivity picking up on vibrations that were always present. Recognising these limitations is key to interpreting your data correctly and avoiding unnecessary alarms.
6. Failing to Act on the Data
Vibration data is only useful if you act on it. Simply collecting readings won’t improve your motor’s health unless you set clear alarm limits and use the data to guide your maintenance efforts. Alarm limits can be determined through statistical analysis and are invaluable in identifying when it’s time for intervention—whether that’s a simple adjustment, an overhaul, or an electric motor rewind.
Without action, you’ll quickly find yourself drowning in data with no practical way to leverage it. Worse, you might miss the opportunity to address potential failures before they escalate into costly problems.
7. Assigning the Wrong Analyst
This last mistake may be the most crucial, as having the right analyst can prevent many of the other issues we’ve discussed. So, how can you identify the right person for the job?
The wrong analyst will rely on rigid comparisons—like matching machine readings to a static wall chart—to diagnose problems. A good analyst, on the other hand, is a curious and detail-oriented investigator who goes beyond surface-level data. They have a deep connection to the machinery, the ability to recognise subtle patterns, and the communication skills to explain their findings in a way that drives action.
Conclusion
To ensure a successful vibration analysis program, take care to avoid the mistakes discussed above. Most importantly, invest in a skilled analyst who can bridge the gap between raw data and actionable insights. If your program falls short, it’s not the fault of vibration analysis itself but rather the way it was implemented. Keep the contents above in mind and you will unlock the full potential of vibration analysis as a powerful tool for maintaining your equipment’s health and efficiency.
