Fan vibration spectrum analysis
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One of the spring-mounted fan units in our factory has a fan speed of 1000 RPM, while the motor rotates at 1440 RPM. Why is the frequency 1.6 times higher? Please give me some guidance.
Hello, could you please advise where it might be loose? I’ll check again
The components of the bearing housing are loose; for example, the radial fit clearance between the outer ring and the bearing housing is out of spec.
Hello, I reduced the clearance of the bearing today. Initially, the clearance between the bearing cover and the outer ring of the bearing was 0.16 mm; I added 0.15 mm of stainless steel sheet, but there was no change in vibration levels. My bearing model is 22212EAKE4, and the bearing housing is of the SNK type. I wonder if such bearings require additional tension?
No additional preload is required radially, but preload is necessary for the axial outer ring.
1450/60=24, p=24; based on the figure below, it can be determined that the excessive vibration is caused by rotor imbalance.
This post was last edited by tie008 on 2018-3-5 at 18:22. I disagree with the opinion above; if it’s a problem with the fan rotor balance, then the vibration frequency should be around 16.8 Hz, not around 27 Hz~~~ I agree with the opinions of the users above – for the 222XXX bearings, there should be some tension in the outer ring~~~ I think an interference fit of +0.05 mm would work better.
The outer ring of the bearing is relatively thin, so using the lead wire compression method to measure the tightening force is inaccurate. Carefully inspect and clean the midline; take a look. I’ve just started learning about spectrograms; this is just my attempt to contribute something to the discussion.
Hello, the speed of the motor is approximately 1450 RPM; it is driven by a belt, and the actual speed of the fan is 1005 RPM. Therefore, your calculation of PS is incorrect – or maybe there’s an issue with your response!