Evaluation - Interpretation of vibration measurements EasyBalancer EB 3500
10 - 10
Possible cause Comment Appearance Confirmation of cause
Tooth defects High radial and low
axial vibration
Check gear stages.
Often also 2x f and 3x f compo-
nents
Vibrations with double mains frequency
Out-of-round stator bore or
rotor misalignment
High radial and low
axial vibration
Check concentricity
and clearance.
Vibration disappears
when switching off.
Vibrations with multiple rotational frequency
Loose High radial and low axial
2x f vibration
Check connections.
Often also 1x, 3x
and 4x f components
Flat and centring errors in
couplings
High radial and low
axial 2x f proportion
Check alignment.
Additionally high radial
2x f proportion
Rotor anisotropy, heavily
grooved rotor
2x f proportion
Only with horizontal shafts.
Speed-dependent static
sag
Shaft with crack 2x f proportion Difficulties with balancing.
Also 3x f proportion
Vibrations at parts of the rotational frequency
Rubbing Slight periodic rubbing can be
seen on vibration components
with 1/4 x, 1/3 x, 1/2 x, 2/3 x
and 1x f
Check clearance, offset
and concentricity.
Also 1/2 x, 1x, 11/2 x and
2x f possible
Slow drift of the phase
position.
Plain bearing instability Vibration with 0.4 x to
0.5 x f
Change oil temperature
and thus oil viscosity.
Further measures by
machine manufacturer
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