The plot below was recorded on the outboard fan pedestal on a variable-speed-controlled motor-gearbox-fan. As the fan slowed down, there was a 4× increase in vibration. This pedestal is situated on the eighteenth floor of an office building. There is no way to increase the stiffness of the pedestal. What should this customer do to prevent the fan from stopping at this obvious critical frequency?

Transcribed Image Text:

Pedestal Resonance Point Maximum Speed Frok Hag MACHE SINGLEFONT C 405