User's Manual

Data Transfer An application within AMS Machinery Manager that facilitates the transfer of data in
the form of a route between the AMS Machinery Manager database and analyzers.
data units The units that are used to display the measured data. The analyzer can display data
in the sensor's units (no conversion), or vibration sensor units can be converted to
acceleration, velocity, or displacement.
decibels, dB A relative, logarithmic unit which can be used when measuring signal amplitude.
displacement
Refers to the distance that an object moves, usually considered to be the overall
range of movement; measured in mils or microns. Displacement is often measured
from eddy current probes and represents the physical movement of a rotating shaft
relative to its supporting bearing.
Sometimes accelerometers or velocity probes are used, and the data is integrated
into displacement. In this case, movement represents the displacement of the
equipment casing where the probe is mounted.
equipment Machinery that includes one or more rotating, stationary, electrical, and structural
components such as motors, gearboxes, fans, and pumps, for example. Each
component has a set of measurement points.
fast fourier
transform, FFT
An efficient computational process which allows the conversion of a signal's time
waveform into a frequency spectrum.
fault An alarm level which indicates that a piece of equipment or a component has failed.
Designated as a "D" alarm in reports.
fault frequency set A set of pre-defined frequencies where mechanical faults are expected to occur.
filter A device which removes certain frequencies from a signal while preserving the rest
of the signal.
frequency Number of times an event repeats in a unit of time; usually expressed in hertz (Hz) or
cycles per minute (CPM).
fundamental
frequency
The frequency of the peak from which related harmonics are referenced. 1xRPM is
an example of a fundamental frequency.
g's The unit of measure for acceleration; 1 g is defined as the acceleration due to gravity
at sea level.
gear mesh
frequency
Asynchronous vibration frequency associated with each pair of meshing gears.
Calculated as RPM divided by 60 times the number of teeth on a particular gear.
Hanning Type of window applied to waveform data before frequency analysis; used to
prevent peaks in a frequency spectrum from spreading out due to a phenomenon
called leakage. The Hanning window is recommended for most frequency analysis
measurements where the signal is steady-state.
harmonic An integer multiple of a fundamental frequency f0 (example 2f0, 3f0, 4f0, etc.).
harmonic marker A box marker that appears on a spectrum display to indicate the harmonic peaks of a
fundamental peak.
heavy spot The actual location of material causing excess mass relative to the center of rotation.
hertz, Hz The unit of frequency in cycles per second.
high spot The location of the rotor where peak vibration occurs in response to the heavy spot.
Heavy spot differs from high spot due to system lag.
Glossary
264
DRAFT