I usually don’t like to generalize, especially when it comes to people, but I have to say that maintenance and reliability folks are pretty much the same no matter where I go. From the West Coast to New England, the upper Midwest to the Deep South, folks who work with their hands pretty much have the same attitude and personality types everywhere. Mechanics razz electricians and vice versa, and even within one discipline you may have rivalries. One of those is the “Vibe Guys” versus the “IR Guys”. Both sides think they’ve got the jump on the other. With rotating assets, vibe often wins the contest, but there’s one exception to that rule where infrared has a real chance to shine; low-speed equipment.
To be considered “low-speed” usually we’re talking about an operating RPM below 600. Vibration analysis works very well on higher speed rotating equipment, but the not so much with slower stuff. The largest hindrance is the slow rotation speed. To be able to compare resonant operating vibration to anomalous vibration, the sampling period has to be extremely long with lower rotation speeds. Even then the results aren't always conclusive. This being the case, lower speed rotating equipment often is left off of vibration routes.
Thermally speaking however, rotation speed isn't as large a concern. If an anomalous condition exists in a low speed bearing for example, heat will build up due to the friction. At low rotating speed, the heat energy may take longer to reach levels that would allow for conduction from the inner races out to the bearing case where it can be seen, but assuming continuous operation of the bearing, the heat would be visible, especially well in later stage (stage three or four) failure. Take a look at the image below.
This is an image of a low-speed roller bearing on a conveyor system in a bakery. Vibration analysis had failed to find this problem, but it jumped right out at us with our imager. We also listened to it with airborne ultrasound and were able to detect some low level acoustic signatures consistent with bearing impact. The customer was pleased, I think, that we ultimately saved him a lot of “dough”. You see, we found this problem in a bakery ... never mind. Bad joke!
Again, the heat buildup is independent of the rotational speed. So in this bearing, which is in continuous use, the internal failure is readily apparent thermally. This is usually true of other low speed rotating equipment, the types of which vibration analysis is usually not applied. So when other reliability technologies fail for mechanical applications, you often can bring IR to the rescue.