A multi-stage blower is vibrating, and spectral analysis reveals an abnormality at the 6th harmonic frequency
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After a major overhaul, the vibration levels of one of our company’s multi-stage blowers were initially good, with the vibration levels at both the front and rear bearings being within 2 mm/s. However, one day the vibration levels suddenly increased; upon inspection, it was found that the rotor of the blower was loose. After tightening it, the vibration levels returned to normal. A few days ago, the vibration level increased suddenly again; spectral analysis revealed an abnormality at the 6th harmonic. What could be the cause?
“One day, the vibration suddenly increased; upon inspection, it was found that the fan rotor was loose. After tightening it, the vibration returned to normal. "Then the tight part must have loosened. It’s just for preventing loosening. Also, what is the area you have confined? Does it mean foundation bolts? Installation issues?
6x frequency scaling, 6 fan blades? A factor of 6 by itself usually refers to the rotation frequency of the impeller; looseness is generally not caused by this