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Note: Make sure that the voltage adjuster at the rear of the instrument
is set to the
value
of the line
voltage.
Calibration of the Frequency Scale.
1. For control knob identification
see
Fig. 2. Make sure that the shaker
is not
energized
during
calibration, e. g.
by turning
"Output
Voltage"
to 0.
2.
Connect
the instrument to the power supply,
set
the toggle switch
marked
"Power"
to
"On" and
allow two minutes warm-up time.
3. Set
"Meter
Switch" in position
"Power
Freq-Beat".
4.
Set the
"Scanning Speed
Multiplier" in position
"Off".
5. Set the knob marked
"Frequency
Range" to
"5-5ooo
c/s".
6. Set
"Compressor
Function" switch on
"Off".
7. Set
"Output
Switch" to
"Linear"
(or "High
Pass").
8.
Turn the
"Oscillator
Frequency Dial"
so
that the pointer points at the
frequency
equal
to that of the line voltage. The instrument meter
pointer will now
start
fluctuating.
9. Turn the
"Frequency
Scale Adjustment" knob until the fluctuations on
the meter become
slower and
finally
almost crease.
The fluctuations
begin again when the
critical
point is passed. If the
adjustment
knob
does not
give
a satisfactory regulation, the
screwdriver
operated capacitor
below the knob
should
be
adjusted.
10. Set the frequency dial pointer to a frequency
equal
to
%
of the mains
voltage
frequency
and
repeat item
9.
The instrument is now ready for use.
Oscillator frequency
checks and
adjustments
can
be made
even
when the
complete vibration
test
arrangement
is operating. The
"Scanning
Speed
Multiplier"
should
then be
set
to
"Off" and
the frequency dial pointer to
the frequency
of
the mains
.
The procedure is then the
same
as outlined
above
in item 3, 8
and
9.
Note:
To carry out the
check
during
operation
the voltage measured on the
instrument meter
at
the frequencies used for
calibration
must be
greater
than 1 V with the
"Meter
Switch" in position
"Oscillator
Voltage".
Adjustment of the Automatic Frequency Scanning Arrangement.
1. Loosen the
screws
on the
"Oscillator
Frequency Dial" marked
Sa and Sb
on Fig. 6.
2. Turn the "Oscillator
Frequency Dial"
pointer to the low frequency limit
of the range in which it is desired to take measurements, and move
15
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