Specifications

Reference Manual
MHM-97408, Rev. 2
June 2008
CSI 9420
www.mhm.assetweb.com
Appendix C Velocity, PeakVue
®
, and
Temperature
Overall Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page C-1
PeakVue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page C-3
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page C-5
OVERALL VELOCITY The Overall Velocity measurement provides a summation of the
low-frequency vibration energy, which is indicative of fault conditions such as
imbalance, misalignment, looseness, and late-stage bearing problems.
The CSI 9420 uses (low-frequency) Overall Velocity in conjunction with
(high-frequency) PeakVue
TM
to provide a holistic solution across frequency
while optimizing the usage of the limited power and bandwidth available in a
wireless device. The majority of developing fault conditions will be manifested
with a monotonic increase in one or both of these key parameters.
The difference in the vibration waveform and the associated measurement for
Overall Vibration versus PeakVue is depicted conceptually in the illustrations
below. Overall Vibration provides an indication of the total low-frequency
energy in the waveform. PeakVue, on the other hand, provides an indication
of the maximum excursion in the waveform, which is how indications of many
developing bearing faults are first manifested.
Figure C-1. Overall Vibration
(left) and PeakVue (right) charts.
While PeakVue is extremely useful for providing an early indication of
impact-related faults in rolling-element bearings, there are many more general
applications where a low-frequency measurement is more appropriate.
Furthermore, virtually all vibration analysts are very familiar with the Overall
Velocity measurement and use it as part of their existing vibration programs.
As a result, while it may not be possible to obtain a measurement result
comparable to the PeakVue value reported by the CSI 9420 with a non-CSI
handheld vibration analyzer, the Overall Velocity measurement is ubiquitous
throughout the industry and should be easy to correlate with the results from
handheld instruments.