Vibration Analysis vs. Motor Analysis for Industrial Motors: The Value Driver Is Evident
Properly timed maintenance of electric motors is essential to maintaining operations in industrial facilities. The alternative is potential motor failure leading to expensive, unplanned downtime and possibly damage of other equipment. From worn bearings to rotor imbalance, effective detection of mechanical problems in rotating equipment, with corresponding corrective action, can identify issues that will eventually result in equipment failure and even damage if not addressed.
Vibration Analysis: The Logical First Choice
Despite the popularity of motor analysis in many forms for nearly a century, from my perspective, vibration analysis, or VbA, is the most logical choice to apply first. Furthermore, it will detect by far the most failure modes compared to other technologies.
Vibration analysis measures the vibration levels and frequencies of industrial machinery. Measuring the amplitude and frequency of vibration enables quick detection of mechanical issues such as worn bearings, rotor imbalance, coupling and bearing misalignment.
The data collected during vibration analysis flows into a software-based data collector, which records the signal as either amplitude vs. time (aka time waveform), amplitude vs. frequency (fast Fourier transform) or both. This data is then analyzed by computer algorithms, which in turn are used by experienced vibration analysts to diagnose equipment problems.
Vibration analysis provides invaluable data to help avert equipment failure. Early problem detection enables facility maintenance teams to proactively resolve troubling issues. In cases where machinery is also sensitive to external vibration, analysis helps to identify how and from what source the vibrations are being transmitted, which enables effective isolation. The advantages of vibration analysis include:
- Save on repair and production costs while dramatically reducing production downtime
- Conveniently schedule maintenance repairs; minimize maintenance costs
- Promote equipment reliability, which also extends the life of very expensive machinery
- Reduce the incidence of major repairs and catastrophic failures
Perhaps most importantly, using vibration analysis minimizes planned downtime, as vibration measurements are taken while equipment is in operation. No shutdowns of any length are required.
Motor analysis, by comparison, falls into the broader description of “motor testing,” which is a general term to include both online and offline testing. Online motor analysis is usually referred to as motor current signature analysis (MCSA), while offline motor testing is most often called motor circuit analysis (MCA). There are other terms in use as well, but these are the primary designations most industrial leaders see.
Here at I-care, we have been watching the evolution of both vibration analysis and motor analysis since our founding. Furthermore, many of our experts have decades of experience in industrial reliability and the mechanisms by which it is promoted. I have watched with interest how newer companies that perform MCSA services have begun promoting the idea that they can detect most mechanical defects, not only on the motor but also on the driven components, just as well as vibration analysis. That is simply untrue. Vibration analysis is a much more reliable technique for the detection of most mechanical defects.
Undoubtedly, there are many applications where MCA and MCSA will prove to be very useful techniques to improve reliability of production and minimize maintenance costs. Motors that will often run in high-load conditions will more likely experience electrical defects related to the rotor or stator. MCA and MCSA will be more effective than vibration analysis in detecting those defects.
In short, vibration analysis is more versatile and remains the logical choice for most applications, while MCSA/MCA techniques will be more ‘focused’ on specific defects. For that reason, they may certainly be justified in certain cases (e.g. large motors, critical and heavily loaded installations). However, vibration analysis will be cost-effective in more applications than MCA/MCSA.
Furthermore, vibration analysis is a much better option for the detection of mechanical problems. That makes vibration analysis an extremely effective method for identifying the early stages of equipment wear and pinpointing potential process breakdowns or degradation before equipment reaches the point of imminent failure.
In summary, vibration analysis is ideal for equipment in facilities where mechanical defects will likely lead to catastrophic failures and costly production losses if not caught in time. It is also the best approach for organizations with high downtime costs, high failure probabilities and high environmental and safety risks.
Although this article has focused on the benefits of VBA over motor analysis, it’s important to remember that there are other methodologies, as well. These include thermography, visual inspections and in some cases, oil analysis or lubrication analysis. These are all complimentary to vibration analysis, but none of them are more useful in preventing catastrophic failure.
When firms work with a seasoned data collection and analytics specialist such as I-care to glean maximum insight from their vibration data, the benefits they will receive and the proactive intervention in which they can engage will amplify the value of their investment.
To connect with Kris and further explore this topic or any other condition monitoring techniques, please click the following link.