K
We have GE Frame 9 unit rated 120MW operating in combined-cycle mode. We are observing that recently when we reduced load on the unit from base to 90MW, vibrationof bearing #3 increased from 3.8/3.9 to 5.14/6.15 mm/sec. vibration reduced to almost previous value after the load on unit was increased to base load. A 1.5mm/sec increase in vibration of bearing # 2 was also seen. What can be reason for this phenomenon? All other parameters remained unchanged. Thanks.