Fluke 810 User Manual page 146

810
Users Manual
amplitudes can be closely related to the running speed of
the machinery. The diagnostic technology in the Tester
identifies the mechanical problems depicted in the
spectra and cites the abnormal magnitudes.
Tachometer. A device for indicating rotation speed.
Tangential. One of the three vibration axes (Radial,
Tangential and Axial), the tangential plane is positioned
90 degrees to the radial plane, running tangent to the
driveshaft. For typical horizontal machines, tangential
equals the horizontal axis. For typical vertical machines
tangential equals the second horizontal axis
perpendicular to the mounting of the accelerometer.
TEDS. A Transducer Electronic Datasheet (TEDS) is a
technology that enables communication of the Sensor
type to the Tester. TEDS works with the Tester to ensure
the Sensor performs at its specified sensitivity, ensuring
optimal performance, and reminds the user when the
Sensor needs to be calibrated.
Time Waveform. The plot of a vibration signal in the time
domain with the signal's amplitude (y-axis) against time
(x-axis). The time waveform represents the signal as
directly captured from the Sensor. The Tester does not
store time waveforms unless users opt to capture them
within the Tester's settings. Time waveforms can only be
viewed in the Viewer software and they can be exported
to a file if further analysis is desired.
C-4
VdB (Velocity in Decibels). VdB is a logarithmic scale
referencing 0 VdB=10E-8 meter per second. This scale is
used for US measurements.
VdB* (Velocity in Decibels). VdB* is a logarithmic scale
referencing 0 VdB=10E-9 meter per second. This scale is
used for SI/metric measurements.
Velocity. Velocity is the rate of change in position,
measured in distance per unit of time. When measuring
vibration signals, velocity also represents the rate of
change in displacement and is expressed in inches (in) or
millimeters (mm) per second.
VFD (Variable-Frequency Drive). A VFD is a system for
controlling the rotational speed of an alternating current
(AC) electric motor by controlling the frequency of the
electrical power supplied to the motor.
Vibration. Vibration is the oscillation of a point, an object,
or a part of an object around a fixed reference, or rest,
position. An object can vibrate as a unit, in which case it
is called "whole body vibration", or, as is usually the case,
an object can vibrate in a complex way where it deforms
and different parts of it vibrate at different frequencies and
amplitudes.