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After calibration the Accelerometer is unscrewed from the
shaker
table, and
the power
supply
is disconnected from the Preamplifier.
NOTE: Protect the connection cable between Accelerometer and indicating
apparatus by removing the cable from the Accelerometer before this
is dismounted.
During the following adjustment and measurement the position of the
"Sensitivity Adjustment" should not be altered, otherwise the calibration
will be lost.
Adjustment to the Vibration Signal.
1.
Mount the Accelerometer on the object to be investigated.
2. Connect Accelerometer to "Input" of Preamplifier.
3. Set indicating apparatus in position
"Linear"
and check that the indicat-
ing meter does not show a higher voltage than indicated in Fig. 4. If
necessary, the voltage can be brought below the stated peak voltages
by attenuating the input voltage to the Preamplifier with control knob
"Attenuation".
4. Select RMS, Average or Peak {half peak-to-peak) type of detection by
the "Meter Switch" on the indicating apparatus. If the B
&
K Level
Recorder Type
2305
is used for recording the results, the appropriate
type of detection is selected by the "Rectifier Response" switch on this
apparatus.
l\leasurement.
I. ACCELERATION
14
Keep Integration Switch on "Acceleration".
1. Accelerometer with Sensitivity Higher than 15 m V /G.
The value of the acceleration in cm/sec.2 is then achieved as follows:
Read value in Volts X 103 X the value indicated by switch "Attenu
ation" of the Preamplifier.
Example:
Meter reading: o.4 V
Position of "Attenuation": "102"
The acceleration will then be: o.4 X 10'
X
102
=
40ooo
cm/sec
2
2. Accelerometer with Sensitivity Lower than 15 mV/G.
Read
value
in Volts X 103 X 10 X the value indicated by switch
"Attenuation" of the
Preamplifier.
Example:
Read value and position of
'
Attenuation"
are
as in example above.
The acceleration will in this case be: o.4 X 10' X 10 X 102
=
400ooo cm/sec
2
•
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