Equipment Centerhung Fan
Problem :starting Vibration at motor and fan upon start lasts for 1or two seconds reaches 8 mm./sec sometimes and it doesnt give same behaviour at every start runs between (4 and 8 mm./sec) then after than it damps again to 2 mm./sec
the vibration occurs only at start for few seconds and then vanishes.
Motor :induction motor 3 MW with LRS (liquid resistance starter).
Tests performed :
Cascade plot before and during the start to capture the frequency of the amplification, using the multichannel analyzer to capture the motor and fan instantenoues (at the same time).
Peak-Hold Averaging to detect the maximum peak at the start.
at all tests the captured frequency which amplifies the vibration at start is 50 hz at both fan and motor.
this test was detected the freuquency but the amplitude was not very high