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3. DANGER – RED COLOUR
There is an serious defect found on the machine. Machine shouldn't be in operation
Overall PEAK values
Similar rules for evaluation of the measured values, as in the previous screen are valid for this screen
with one difference. The peak (PEAK) vibration values are displayed. It is highest measured value in
certain time, which is important for transient shock events evaluation, especially in cases of incipient
bearing defects, like:
- microscopic peeling off of a hardened surface layer in the place of a rolling element contact
with a bearing ring (regular shocks),
- contamination of bearing space by metal particles (irregular shocks),
- cracks.
The shocks that cause these defects are also parts the RMS vibration values. However, the peak
value of such shock is hidden in a value which contains all other information about vibrations, i.e.
noise from possible abrading, wrong lubrication and overloading. To simplify, the RMS is an average
value of all vibration values achieved in certain time. If a large peak value (one shock) appears in this
time period, it will be lost in the final recalculation of all the values.
This practically means that during increasing of this bearing defect that causes the shock, the PEAK
value of this shock will visibly increase, while the effective (RMS) value will increase only slowly. We
can discover the initial defect time of the bearing sooner. But PEAK value is not so stable as RMS
value. For bearing condition measurement is the RMS measurement sufficient.
Spectrum 200 Hz– Detection of Looseness
This screen is important for detection of the the mechanical looseness. When the graph shows a
number of lines ( typically 3 or 4) with the same space between them and the first line is on the speed
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Adash 4900 – Vibrio III
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