We have Siemens SGT 300 ( 7.5 MW) Gas turbine Generator.
During starting of this machine heavy vibration observed and machine tripped at 9000 RPM on high vibration ( Vibration tripping set at 90 Microns). More than 15 trial taken in this machine neglecting vibration. On opening this machine cold end bearing found damage. Photographs attached. What is probable reason for this bearing failure??