1 fan blade(frp) in A336" diameter fan assembly has been found in catastrophic failure condition and drive shaft(metal) also found in bent and broken condition on ground.
What are the possible root causes??
Fan blades already have replaced with new blades.
Drive shaft also has been replaced with coupling and rebalancing has been performed also. But no effect on vibration.
Fft showing mechanical looseness on 570 rpm but we already have checked all base casting,structure joints,foundation joints of...
High vibration has been observed horizontally in motor DE&NDE as well as in gear box in a newly build 4 cells Cooling tower of Pultruded FRP material after commissioning of 20 month.
High vibration has been observed in motor mounted on 3rd cell and vibration is 12 to 14 mm/ses (RMS Value) at 570...
