Secrets of Simon Building 3

One fine morning, Prof Henry took me down to the basement of Simon Building. There he asked me to listen to the sound of two compressors running — a ho-hum sound. The sound rose and fell rhythmically.

“This is what a beat sounds like,” he remarked.

He quickly followed it up by some rapid fire questions, “Now, what else do you see? What causes a beat? How would that appear on a time waveform and a spectrum? Why would it appear so? What damage might it cause to a machine? And what may we do about it?”

Over the day, as I slowly unraveled the answers, which incidentally weren’t difficult, I reflected upon the incident. Surely, he was trying to teach me some important lesson by taking me down to the basement.

Then all of a sudden the import of the incident struck me.

First, it was important for an engineer to be close to a machine and sense it physically before one gets down to analytics. One’s senses have to be tuned to receive and understand the gross signals a machine sends out. And while sensing those signals one also looks for others clues, abnormalities, imperfections of the system. For instance, the degree of looseness of the base bolts or the temperature of the motor or temperature of the bearing etc. The analyst then starts linking all these in his/her mind. It is “relational mapping”, if I may call it so.

Second, one also has to make sense of the context and “see” the relationship between different machines. The interdependence has to be seen and felt. Like different components of the machine are interdependent on each other; different machines are also interdependent on each other and so are the interactions between a machine and the material or fluids it handles. Such interdependence and interactions create different patterns. For example, beat is one of such pattern while cavitation or water hammer are other examples of patterns arising out of interactions. An expert analyst actually looks out for such patterns which reveal the interactions taking place within and without of a system . I call this “pattern sensing”.

Only after one has gained a deep understanding of “relational mapping” and “pattern sensing” the vibration signals in terms of overall vibration trends, comparative trends with other signals, time waveform, spectrum or signature etc spring to life and begin to make sense. And once we may do something to correct a situation the joy of creativity takes over.

© Dibyendu De