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Figure 12.5. The gauge head can reduce instrument errors to as low as 0.05% with repeatability of
0.0001 mm.
Angular displacement can also be measured using inductance techniques employing
a rotary variable differential transformer (RVDT). The output curve of an RVDT and a
typical construction are shown in Figure 12.6, in which the linear output range is approximately Æ40 degrees.
Measurement of Acceleration and Vibration
The measurement of acceleration is required for a variety of purposes, ranging from machine design
to guidance systems. Because of the range of applications for acceleration and vibration measurements, there exists a wide variety of transducers and measurement techniques, each associated with
a particular application. This section addresses some fundamental aspects of these measurements
along with some common applications.
Probe shaft
Mounting thread
Connector
LVDT
Bearing
Tip
Spring
Figure 12.5 LVDT gauge head. Top: Cross section of a typical LVDT gauge head. (Courtesy of Schaevitz
Engineering; from reference 2.)
12.2 Sensors 509