EasyBalancer EB 3500 Evaluation - Interpretation of vibration measurements
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Possible cause Comment Appearance
Confirmation of
cause
Vibrations without direct reference to the machine frequency
Background vibrations Vibration source also outside
the machine
Switch off machine
and measure remaining
vibration.
Natural frequencies N Frequency N given by machine
design
Excite natural frequency
by striking with a hammer.
Resonance R Excitation frequency
(e.g. rotational frequency) co-
incides with natural frequency
When the speed chang-
es, vibrations near the
resonance increase
greatly.
Frequency does not change
with speed / rotational frequency
Critical speed K Machine shaft deflects see resonance.
Beat Falling and rising vibration
caused by superposition of two
vibrations with approximately
the same frequency
Recording of vibration
over time.
Self-exciting vibrations
due to
- Plain bearings
- Seals
- Shaft-hub connection
Vibration frequency does
not change with variation
of speed.
At low speeds essentially
1x f component.
Above a certain rotational
frequency, the frequency
of the self-excited vibra-
tion dominates.
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