B
In 210 MW turbogenerator at rated 3000 RPM, bearing no. 7 axial vibration increased to 150 microns. Also in bearing no. 6 vertical and axial increased. When the turbine is spinning the vibration is normal up to 1200 RPM. Only above 2000 RPM the vibration increased in bearing no. 7 axial. Spectrum shows 1x RPM frequency in bearing no. 7 axial. Can anyone suggest the cause?
