
I-2
72A-1898 Rev. A 11/01
Monday
, November 26, 2001 1:09 pm
A matching set of apertures are located in a fixed plate. The light beam is
transmitted only when the apertures are aligned, which produces a light
pulse for each aperture. A molded lens beneath the base plate collects
the modulated light and directs it to a detector.
There are two identical channels. Each channel consists of two
photodiodes, an amplifier, a comparator, and output buffers. The
apertures for the two photodiodes are positioned so that a light period on
one detector corresponds to a dark period on the other. The photodiode
signals are amplified and fed to the comparator whose output changes
state when the difference of the two currents changes sign. The second
channel has a similar configuration, but the location of its aperture pair
provides an output which is in quadrature to the first channel (phase
difference of 90 degrees). The direction of rotation is determined by
observing which of the two channels is the leading wave form. The
number of pulses encodes the angular displacement of the disk. This
pulse train is converted to a number which is stored in memory at a
regular interval. This interval produces a time reference which is used to
plot displacement per unit time, or instantaneous velocity. The motion
plot is produced by plotting the sum of the displacement data vs. time.
The delta displacement for each sample interval represents the total
displacement which has occurred during the sample interval. Therefore,
this data can be translated directly into velocity, which is then plotted for
each time interval.
There are a number of different ways the TR3190 Motion Transducer can
be interfaced with a breaker. For applications where part of the
accessible breaker mechanism exhibits linear motion, the following
method may be employed:
The transducer is designed to couple to a 1/4" Mild Steel connecting
rod, which must be 0.250"
±
0.010" and free from nicks or burrs.
Select a point on the breaker mechanism, as close to the contacts as
possible, that exhibits linear motion in one plane. The top of the lift
rod on most Dead Tank oil breakers is provided with a #10 x 24
threaded hole for this application. This threaded hole is typically
accessible through a small hole located under the cap for the stop
adjustment on the center tank. If this attachment point is not
provided, it is still possible to attach a rod to other points on the
breaker. For instance, it is often possible to access the lift rod in the
cabinet of the breaker. A collar could be fabricated which attaches
around the lift rod, and provides a place to attach the 1/4" connecting
rod. The transducer connecting rod will accommodate 15° of angular
displacement. This displacement must be in a plane parallel with the
Содержание TDR9000
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