We have a 324 Generator with high Harmonic Noise Index (HNI) numbers.
The HNI measures vibration interaction between the generator core and keybars aka keybar rattle. Unit starts about 300 times per year. Three belly bands were installed when the unit was manufactured. We understand some bellybands installed in the fleet may have been manufactured incorrectly. We have a few options under consideration at this time which includes replacing the 3 belly bands, replace and add 2 more belly bands, retighten the existing belly
bands and at the same time retorque the keybar nuts. What is your experience with resolving this issue? Please share your feedback and any lessons learned.
thanks