Air Compressor Vibration
Air Compressor Vibration
(OP)
We have installed a Ingersoll-Rand Type 30 Model 3000X30 air compressor. This is a two stage three cylinder 100 psi 100 ACFM electric motor driven machine.
Per the direction of the vendor who supplied the machines, we shimmed under each of the holddown bolts of the base plate to correct vibration problems. The procedure was to loosen one bolt and lift the corner of the base plate, if vibration decreased we shimmed under this point and retightened the bolt. This worked just fine on one of our machines. On the other machine this did not solve the vibration problem. To get an acceptable vibration level the mechanics had to leave one of the bolts loose. They found that putting shims under the holddown point or even running the nut down finger tight would cause the machine to vibrate. Either of the holddowns across from each other will do this. The machine presently has three bolts tight and one loose and the vibration is acceptable. Any suggestions to the cause?
Per the direction of the vendor who supplied the machines, we shimmed under each of the holddown bolts of the base plate to correct vibration problems. The procedure was to loosen one bolt and lift the corner of the base plate, if vibration decreased we shimmed under this point and retightened the bolt. This worked just fine on one of our machines. On the other machine this did not solve the vibration problem. To get an acceptable vibration level the mechanics had to leave one of the bolts loose. They found that putting shims under the holddown point or even running the nut down finger tight would cause the machine to vibrate. Either of the holddowns across from each other will do this. The machine presently has three bolts tight and one loose and the vibration is acceptable. Any suggestions to the cause?





RE: Air Compressor Vibration
RE: Air Compressor Vibration
our compressor is the 30X3000 at the bottom.
The compressor is belt driven by a 30 HP 1460 RPM electric motor. The motor hold down bolts are about five inches back from the baseplate bolts. They are about four inches in from each base plate bolt. The baseplate bolts are 39" center to center on one side and 19" center to center on the ends.
I do not have information regarding frequency of vibration.
Thanks,
Jim
RE: Air Compressor Vibration
If these are new installations, then consider getting an independent vibration analysis and get the vendor to fix the problem. Leaving one base bolt loose is not a solution. Pls let us know how this turns out.
RE: Air Compressor Vibration
RE: Air Compressor Vibration
As stated by brin, you're checking for soft foot propblem. You need to check both alignemnt and resonance within the operating speed of the machine.
When holding the forth bolt, you are making the system more stiff and this could cause the system natural frequency to be excited. Usually the separation margin should be 15-20 % away from the excitng running frequency.