Field case · Condition monitoring
Motor cooling fan at a steel mill: a resonance warning, and a fan that broke ten days later
Quick answer
High, unexplained peaks in the spectrum of a mill motor did not match any forcing frequency. The fan was noisy, and the noise went away whenever a bar entered the mill. The client was asked to inspect the fan for cracks; ten days later it broke.
What the case covers
- What was seen
- Why it is resonance
- The outcome
- What to take from it
Takeaway. A hump in the spectrum that is not on a multiple of speed is a resonance. The fan failed ten days after the warning because no stop was possible.
Read the full case, with the data and the numbers