Noise and vibration occuring at 120, 126 and 162 motor harmonics
Noise and vibration occuring at 120, 126 and 162 motor harmonics
(OP)
I'm coping with a new compressor drive train showing noise and vibrations peaks at 120, 126th and 162th motor order. I haven't found a plausible explanation for this orders. What can be the cause of such high motor orders? They don't coincidence with any of the typical frequencies one can expect when dealing with gearbox drive arrangements (gear mesh frequency, bull gear frequency, pinion frequency, ...)





RE: Noise and vibration occuring at 120, 126 and 162 motor harmonics
Skip Hartman
http://www.machinerywatch.com
RE: Noise and vibration occuring at 120, 126 and 162 motor harmonics
RE: Noise and vibration occuring at 120, 126 and 162 motor harmonics
It would probably help if you can provide any of the following info which is available:
Is vib higher on motor or compressor?
What is motor speed?
What is compressor speed?
Is there a vfd?
Describe gearbox configuration including # of teeth
Describe compressor
If we're talking a machine 1200 rpm or lower it's possible this might be ringing from bearing impacting. Are you sure these frequencies clearly syncronous (exact multiples of running speed? Are these sleeve bearings or anti-friction and if anti-friction do you have manufacturer and part number?
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RE: Noise and vibration occuring at 120, 126 and 162 motor harmonics
Some extra data:
- it's a screw compressor with 4 lobes on male and 6 lobes on female
- vibration peaks remain at same frequencies, regardless of gear sets (different transmission ratios have been tried)
- motor speed is around 1500 rpm (4 pole AC motor)
Rotor Bar Pass Frequency? Is this something similar as Slot Frequency?
RE: Noise and vibration occuring at 120, 126 and 162 motor harmonics