I have a case of abnormal vibration at both side of steam turbine which I hope to receive your comment/ideal of the root cause on this issue (pls see in file attachment for your information).
Some information as below:
The pump is boiler feed water pump which is driven by a small steam turbine (Dresser Drand as OEM, turbine is impulse turbine) through a reducer gearbox.
On 14/11/2014 the pump was taken into operation after conducting overhaul for all pump trains. The vibration at pump and gearbox is normal but in both side of steam turbine, it is abnormal with vibration fluctuating unstably (as the vibration trend below).
As operation confirmation that the operation parameter like flow, pressure of steam is normal.
All clearance is in acceptance as OEM specification.
Thank you in advance.