During Gas Turbine (GE Frame 5) run when the machine was started and loaded till 4MW, rise in vibration observed towards Generator DE bearing and it touched the alarm levels (0.5 in/ s pk) in the panel.
During this time no major change in 1X of generator frequency but rise in 1X of HSS frequency is observed. The machine was loaded to 10 MW & the amplitudes gradually settled down. The load was again reduced to 4MW & the amplitudes again started increasing on generator DE bearing.
The observation of 1X of HSS appearing in vibration signal of generator bearings (LSS) could be due to possible mis-alignment of the machine train. Kindly confirm.