We have experienced dramatic change of vibration over GT24 "SGT600" where bearing 3, 4.
We have stopped the unit and start it again and vibration trend still high, specially bearing 3.
We also carried out NDT test on PT coupling shaft but found no trails for cracks!
The high vibration parts are shown in following schematic:
the attached files contains all the required data.
any suggestions about this?? it will be appreciated