Amer93
Mechanical
- Feb 21, 2021
- 10
Greetings,
I'm currently troubleshooting a centrifugal gas compressor with high vibration and would appreciate your technical opinions on the matter. The compressor is a Dresser Clark 40+ years old 3-stage driven by a 6000 hp induction motor through a gearbox with a rated speed of 9200 rpm. It was overhauled approximately a year ago and operated satisfactorily for several months. The compressor was then down for 4 months due to switchover and T&I activities in the area. Once started afterwards, increased vibration levels were observed on the X direction of NDE (~2.2 mil pk ____ H = 2.7 mil pk). Y direction = ~1.3 mil pk. DE X and Y are ~1.3 mil pk and ~0.5 mil pk, respectively. The spectrum shows a dominant 1 x with no other peaks. DE has forward precession and NDE has reverse precession. I see high negative energy on the NDE. The compressor is operating under the first critical speed; however, I noticed a phase shift on the NDE only of 90 deg between 3000 - 4000 rpm during startup and shutdown. The shaft centerline shows a movement difference between DE and NDE once full speed is achieved by ~2 mils vertically and ~3.5 mils horizontally. What do you think?
I'm currently troubleshooting a centrifugal gas compressor with high vibration and would appreciate your technical opinions on the matter. The compressor is a Dresser Clark 40+ years old 3-stage driven by a 6000 hp induction motor through a gearbox with a rated speed of 9200 rpm. It was overhauled approximately a year ago and operated satisfactorily for several months. The compressor was then down for 4 months due to switchover and T&I activities in the area. Once started afterwards, increased vibration levels were observed on the X direction of NDE (~2.2 mil pk ____ H = 2.7 mil pk). Y direction = ~1.3 mil pk. DE X and Y are ~1.3 mil pk and ~0.5 mil pk, respectively. The spectrum shows a dominant 1 x with no other peaks. DE has forward precession and NDE has reverse precession. I see high negative energy on the NDE. The compressor is operating under the first critical speed; however, I noticed a phase shift on the NDE only of 90 deg between 3000 - 4000 rpm during startup and shutdown. The shaft centerline shows a movement difference between DE and NDE once full speed is achieved by ~2 mils vertically and ~3.5 mils horizontally. What do you think?