Both
can
be
used
for
calibration
of
accelerometers, vibration
of
small
objects, mechanical impedance measurements.
For
more details
on
their
construction
and
performance, reference should
be
made
to
their
instruction manuals.
When the Power
Amplifier
Type 2706
is
used
to
drive one
of
the
vibration exciters, the CURRENT
LIMIT
should be set
to
"5.0
ARMS"
for
Type 4809
and
to
"1.8
ARMS"
for
Type 4810.
5.2.
1.
Accelerometer calibration
A calibration set-up using the
Mini
Shaker
Type
4810
is
shown in
Fig.5.1.
r-
1
I
Be
at Frequency O
sci
llator
1022
Comp
ressio
n
I
L
______
_
_j
M
ec
hani
ca
l Drive
Sh
aft
UB 0041
Fig.5.1. Example
of
Calibration set-up
Sensitivity
of
the
unknown
accelerometer
is
measured
by
comparison·
using the Sensitivity Comparator
Type
2970 together
with
two
Con-
ditioning
Amplifiers Type 2626.
Calibration
is
performed at a fixed frequency (e.g.
160Hz)
and a relative
frequency
response
curve
can
be
recorded on a Level Recorder
Type
2305
or
2307. Full details on the calibration procedure are given in the instruc-
tions manual for Type 2970.
15
To Next Page
Loading...
