Help needed, Reciprocating compresso

[Shahdadfroutan]

Reciprocating compressor, three stages, one piston balance, driver: steam turbine, gearbox BHS 20/1, couplings: metastream( flexible),
We have started turbine+gearbox without any problem, the compressor without gearbox and turbine(with barring) has started without any problems also, but when gearbox is coupled to compressor in both cases of barring and turbine, we observe a hard vibration and high noise over "low speed shaft" which shutdowns the compressor, what is the reason?

 

[nfinit]

How was the equipment aligned?

I would remove a couple valve cages or a cylinder head and inspect internally.
Check for liquid. Check your rider bands and piston rings.
What is the history of the equipment?
What is the process?

too much information needed.

 

[Shahdadfroutan]

Alignment and checking of internal parts have been done before successfully, rider bands and piston rings also have been checked and no any problems are observed, there are 3 compressors with turbine and geArbox, which turbine with gearbox and compressor with electromotor in fabrication shop have been tested successfully, but these three machines ( turbine+gearbox+compressor) together have not been tested before,
During Precommisioning of compressor we don't see any vibration on turbine and compressor, turbine alone and with gearbox had a good result on related tests, but when gearbox is coupled to turbine and we increase the speed of turbine, we observe an unormal vibration and noise which are increasing in amount over low speed shaft that make a shutdown immediately.
Sincerely,

 

[nickelkid]

What are the crankshaft web deflections before without coupling installed and after coupling installed?

 

[Shahdadfroutan]

Before and after are 0.07mm both. Regards

 

[DLite30]

Was there a torsional analysis performed on this setup?

Torsional vibration is usually a silent killer and not generally detectable with normal vibration equipment, but since you have a gear box with allowed a modicum amount of torsional play available, it may be manifesting itself as gear noise and shaft vibration.