Condition Monitoring Expert Tip #8 - Is it important to use wear particle analysis?

First, it is important to monitor the condition your lubricants. You can test the chemistry to determine if the lubricant can continue to do its job. You can also detect contaminants, both particles such as dirt and fluids such as water, because they can harm the lubricant and harm your machine. But if your oil analysis includes particle counting and can detect metallic elements, do you also need to perform wear particle analysis? The short answer is “yes”.

When wear occurs within a machine, small particles are generated. The shape, size and color of those particles indicates where they have come from and how and why they were created. For example, if contaminants caused the wear, the particles will look different to particles generated if there was excessive load. There is an “atlas” available that illustrates what the particles can look like.

The process used to count the particles, which is an important oil analysis test to perform, does not provide an indication of the nature and origin of the particles. And when the oil analysis report indicates that elements such as iron and tin are present, that is only because there were very small particles, less than approximately 9 µm in size, present in the oil. The wear particles we are talking about are a lot larger in size. When these wear particles exist, you may not see any real indication in the standard oil analysis report, and the information gained does not provide the critical diagnostic information need.

This tip is provided by Jason Tranter, Managing Director of Mobius Institute.

For more condition monitoring tips, continue to visit the IMVAC – International Machine Vibration Analysis Conference – blog every week. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

Condition Monitoring Expert Tip #7 - Why do I need to use time waveform analysis?

Spectrum analysis provides a great deal of information about the health of rotating machinery. But you should consider the spectrum as a summary of the vibration within the machine.

The Fast Fourier Transform takes the time waveform and computes how much of each frequency is present and displays that as a line in the spectrum (grossly summarized, but that is basically the case). Therefore, if the vibration from the machine is generated by smooth periodic motion, then the spectrum provides a very good representation of what is happening inside the machine. But as damaged gears mesh together, and rolling elements pass over damaged areas on the raceway of the bearing, and as the pump vanes push through the fluid causing turbulence or cavitation, the vibration generated is not smooth and periodic. And there are a lot of other fault conditions that likewise do not generate smooth and periodic vibration. Thus, the only way to really understand what is happening inside the machine is to study the time waveform.

The time waveform is a record of exactly what happened from moment to moment as the shaft turns, the gears mesh, the vanes pass through fluid, and the rolling elements roll around the bearing. Each minute change that results from impacts, rubs, scrapes, rattles, surges, and so much more is recorded in the time waveform and then summarized in the spectrum. Therefore, it is critical to record the time waveform correctly and analyze it when you have any suspicion that a fault condition exists.

This tip is provided by Jason Tranter, Managing Director of Mobius Institute.

For more condition monitoring tips, continue to visit the IMVAC – International Machine Vibration Analysis Conference – blog every week. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

Condition Monitoring Expert Tip #6 - Why do I need to use phase analysis?

The vibration spectrum can provide clear indication of certain fault conditions, but when you see a large peak at the running speed (1X) what will your diagnosis be? What if you also see peaks at 2X and 3X? Now, if you are monitoring a large fan with a history of the building up on the fan blades, then you may reasonably conclude that the high 1X peak indicates unbalance. But in the more general case, how do you distinguish between unbalance, bent shaft, looseness, resonance, eccentricity, misalignment, cocked bearing, and other fault conditions? This is where phase analysis is your friend.

Once upon a time phase analysis was difficult to perform because most people owned single channel vibration analyzers. But with a two-channel analyzer, and two vibration sensors, it is very easy to perform phase analysis. By simply placing one sensor vertically on the bearing and one sensor horizontally you can determine if unbalance exists. By comparing the vibration from one end of the machine to the other (in the same axis) you can confirm the unbalance diagnosis and assess whether it requires single-plane balance or two-plane. Comparing phase axially across a coupling, and radially across the coupling can help you diagnose and confirm misalignment.

I could go on and on, but phase analysis the best tool for distinguishing between all of the listed fault conditions and more.

This tip is provided by Jason Tranter, Managing Director of Mobius Institute.

For more condition monitoring tips, continue to visit the IMVAC – International Machine Vibration Analysis Conference – blog every week. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

IMVAC Middle East Featured Full Day Workshop – Scott Dow

Practical Vibration Analysis Workshop: Interactive and Challenging Case Studies

by Scott Dow, Senior Instructor, Mobius Institute

The Practical Vibration Analysis workshop, presented by Scott Dow, will provide an opportunity to sharpen your diagnostic skills and strengthen your depth of knowledge. This is no ordinary conference workshop. You will be challenged. You will be made to think. And you will learn essential skills that all vibration analysts must have to confidently diagnose the trickiest fault conditions (that might otherwise leave you frustrated and even embarrassed). Rather than teaching you how to diagnose faults, you will actually try to diagnose faults yourself. You will either learn from your mistakes or gain confidence from your victories.

Join IMVAC in Dubai April 3-5, 2017 to hear Scott Dow and many other great speakers, where you will benefit from their insight, experiences and leadership within the application of machine diagnostics, condition monitoring and reliability improvement. 

Learn more at vibrationconference.com. 

IMVAC Middle East Featured Keynote Presentation – Dean Whittle

Fault Detection, Root Cause Analysis and Documenting Your Vibration Analysis Program

by Dean Whittle, Managing Director, Reliability Maintenance Solutions Ltd 

This keynote presentation starts by discussing a case study looking at the methods, techniques and steps taken in diagnosing the problem. It then asks the question as a vibration analyst – Are we doing our job correctly? Is there more we can/should do? It also examines what we did next in respect to the case study presented. The presentation then concludes by looking at how the analysis and findings were documented and integrated into more comprehensive VA/CBM reporting metrics.

Join IMVAC in Dubai April 3-5, 2017 to hear Dean Whittle and many other great speakers, where you will benefit from their insight, experiences and leadership within the application of machine diagnostics, condition monitoring and reliability improvement. 

Learn more at vibrationconference.com. 

Condition Monitoring Expert Tip #5 - Which is the Best Bearing Fault Detection Technique?

Now this is a tricky question to answer… We have a few contenders: high frequency vibration analysis, regular vibration analysis, ultrasound, oil analysis, wear particle analysis, and infrared analysis. Let's start by ruling a few of them out.

Infrared analysis is used to detect heat in a bearing, which is a late stage fault condition, so that's not your best option. Regular oil analysis can detect the presence of the wear metals within the bearing, but wear particle analysis is a better tool for that. Regular vibration analysis (i.e. velocity spectra) provide very clear indications of bearing faults, however the high-frequency detection techniques provide an earlier warning. That leaves high-frequency vibration analysis, ultrasound, and wear particle analysis.

Ultrasound is easiest to use. Push the probe against the bearing and listen carefully and you will hear if the bearing is in distress. (You can also record and analyze a waveform, but now you may as well be performing vibration analysis). Many would argue that high-frequency vibration analysis (such as enveloping, PeakVue, shock pulse, and others) provide a clearer indication of the nature and the severity of the fault. But it does require more training and potentially a more expensive system to perform the collection and analysis.

And that leaves wear particle analysis. Let's just say that if you own critical gearboxes, you absolutely must perform wear particle analysis. Performed correctly, you will detect the first signs of wear, and complex gearboxes provide a greater challenge for the vibration analyst and the ultrasound tools.

Although I haven't really answered the question, I am hoping to have put you in a position to make the right decision for your situation.

This tip is provided by Jason Tranter, Managing Director of Mobius Institute.

For more condition monitoring tips, continue to visit the IMVAC – International Machine Vibration Analysis Conference – blog every week. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

Condition Monitoring Expert Tip #4 - One technology is not enough

There is no doubt that technologies such as vibration analysis, oil analysis, ultrasound and infrared are very powerful. They can tell you a great deal about fault conditions in rotating machinery, electrical systems, and more. But if the criticality warrants it, you will be in a much stronger position if you have multiple technologies indicating that a fault condition exists rather than relying on just one.

For example, if vibration analysis indicates there is a problem in a gearbox, oil analysis can confirm the fault with the presence of wear particles. In the case of vibration analysis, you can utilize high frequency analysis, spectrum analysis, time waveform analysis, and phase analysis to enable you to validate your diagnosis.

There can be a great deal at stake when you make a diagnostic call on a piece of equipment. More so if it is critical equipment. At the very least, a false diagnosis may lead to equipment failure (if you miss the fault condition) or it can lead to unnecessary work and downtime. What's more, your reputation is at stake. Sadly, people often forget when you make the right call, but it can take years for people to forget when you make the wrong call.

This tip is provided by Jason Tranter, Managing Director of Mobius Institute.

For more condition monitoring tips, continue to visit the IMVAC – International Machine Vibration Analysis Conference – blog every week. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.