150 Rockwell Automation Publication 1444-UM001D-EN-P - June 2018
Chapter 4 Measurement Definition
Spike Energy is a measure of the intensity of energy that repetitive transient
mechanical impacts generate. Repetitive transient mechanical impacts typically
occur as a result of surface flaws in rolling-element bearings, gear teeth, or other
devices where metal-to-metal contact repeatedly occurs by design. But such
contact can also occur as a consequence of abnormal conditions such as rotor
rub or insufficient bearing lubrication. Spike Energy is also sensitive to other
ultrasonic signals, such as pump cavitation, high-pressure steam or airflow,
turbulence in liquids, or control valve noise. Spike Energy is also capable of
detecting random impact events, singular cases of mechanical impact that can
occur at any time, and that impart low energies.
This page is presented when the channel is configured for Spike Energy (gSE)
measurements. See Channel Type selection, General
Page on page 97.
Bands
The FFT Band is a powerful tool that is commonly used in condition-
monitoring applications. It is also useful in process applications such as
detecting the presence of cavitation in a pump or for monitoring the
combustion in a gas turbine. An FFT Band either calculates the total energy or
returns the maximum amplitude, or its frequency, between two frequencies of
an FFT.
The Bands can be calculated from a unique FFT, defined on this page, or from
the gSE FFT if a gSE Channel.
If measuring from a gSE channel then:
• The FFT definition parameters (Sample Source or Number of Lines) are
not used.
• The gSE FFT used for the band measurement is processed using the
parameters that are provided on the gSE page.
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