Oil Whirl

0.38X to 0.48X

radial

Sharp peak

Oil Whip

0.38X to 0.48X

radial

Sharp peak

Run-out at rotor mass appears as imbalance.

Run-out at coupling appears as misalignment.

Excessive Bearing

Clearance

1X harmonics

radial

hump in 1X harmonic series

4X to 8X and/or 7X to 15X

Journal

Bearing

looseness,

Rattling

0.5X, 1X

radial

0.5X harmonics

Journal

Thrust

Bearings,

Kingsbury

1X; shoe rate of Kingsbury

axial

1X harmonics; shoe rate harmonics for Kingsbury

Usually six shoes