Operating Insructions; Turn On Procedure; Applications; Rms Current/Rms Ac-To-Dc Converter - HP 3400A Operating And Service Manual

Model 3400A
Section
m
SECTION
III
OPERATING INSTRUCTIONS
t
3-1.
INTRODUCTION.
3-2.
This
section consists
of
instructions
and infor-
mation necessary for the
operation
of
the -hp-
Model
3400
A RMS
Voltmeter.
This section contains identi-
fication of
controls
and
indicators,
turn-on pro-
cedures,
and operating instructions.
Also included
is
a
discussion
of
the applications for the
Model
3400A.
3-3.
CONTROLS AND
INDICATORS.
3-4.
Each operating control,
connector,
and indicator
located
on
the
Model 3400A
is
identified
and described
in
Figure 3-1.
The description
of
each
component
is
keyed
to
an illustration of that
component which
is
included within the figure.
3-5.
TURN
ON
PROCEDURE.
3-6.
Toturnonthe Model 3400A, proceed as follows:
a.
Set
115/230 switch
(7,
Figure 3-1) to
correct
position for input line
voltage.
b.
Apply
ac voltage
to
Model 3400A by plugging
power cord
into input
power
jack
(8)
ac
receptacle.
c.
Operate power switch
(4)
to
ON; ensure that
LINE
indicator
(3)
lights.
NOTE
Allow five
minutes
for the
Model
3400
A
to
warm
up and
stabilize
before
making a reading.
3-7.
OPERATING
INSTRUCTIONS.
DO NOT MEASURE SIGNAL
ABOVE
80
VOLTS WITH
10
TO
1
CREST
FACTOR. OTHERWISE,
THE
MAXI-
MUM
INPUT RATING
(
800
VOLTS
PEAK)
WILL
BE EXCEEDED.
WHEN
MEASURING SIGNALS
UP TO
80
VOLTS
RMS WITH A
10
TO
1
CREST
FACTOR, USE
THE BNC TO DUAL
BANANA
JACK,
ACCESSORY
101 10A,
SUPPLIED WITH
THE INSTRUMENT,
OR OTHER INPUT TEST LEADS
AND
CONNECTIONS
THAT WILL WITH-
STAND THE
MAXIMUM
INPUT
OF
800
VOLTS PEAK.
3-8.
To
operate the
Model 3400A
as
an
rms
volt-
meter proceed
as follows:
a.
Attach test
lead
to
INPUT
connector
(6,
Figure
3-
1).
(See
Table
1-3
for a
list
of test
leads available.
b.
Set
RANGE
switch
(5)
to
300
VOLTS
position.
CAUTION
WHEN MEASURING AN AC SIGNAL
SUPERIMPOSED ON
A
DC
LEVEL,
ALWAYS SET
THE RANGE SWITCH
TO THE
300
VOLT
POSITION.
A
HIGH
VOLTAGE
TRANSIENT DUE
TO THE APPLICATION OF
A
DC
VOLTAGE WILL
DAMAGE THE
INPUT CIRCUITRY.
c.
Connect test lead to
point to
be measured.
d.
Rotate
RANGE
switch counterclockwise until
meter
(1)
indicates
on upper two thirds of scale.
3-9.
APPLICATIONS.
3-10.
The Model 3400A
can be used
in
conjunction
with other test
instruments
to
measure
the
rms
value
of
ac signal with a dc
component,
measure
rms
current and
act as
an
rms
ac-to-dc converter.
For
additional
information
on
special applications, contact
your -hp-
Sales and
Service
Office.
3-11.
RMS VALUE OF
AC
SIGNALS
WITH DC
COMPONENT.
3-12.
Since the
3400A
is
an ac device
it
will
measure
only the
rms
value
of
the ac
component.
If it
is
nec-
essary
to
include the
rms
value of
the dc
component
when measuring a signal
use
a-hp-Model 412A
DC
Voltmeter
to
measure
the
dc component.
Substitute
the
reading
from
the
Model 412A
and
Model 3400A
in
the following
formula:
The
ac signal (up
to
800V
peak)
may
be
superimposed
on a dc
level of
up
to
600
V.
rms
4
ac 'dc
3-13.
RMS
CURRENT.
3-
14.
To measure
rms
current, use an -hp-
Model 456A
AC
Current Probe.
This probe
clips
around the
current conductor
and provides an output voltage that
is
proportional
to
the
current being
measured. Using
this
method,
rms
currents
of
one milliampere
to
one
ampere can be measured.
3-15.
RMS
AC-TO-DC CONVERTER.
3-16.
Since the
Model 3400
A
is
provided with a dc
output
(10,
Figure
3-1)
which
is
proportional to the
meter
deflection,
it
can be used
as a
linear
rms
ac
to
dc converter.
The
dc output
can
be
used
to
drive
a
-hp-
Model 3440A
Digital
Voltmeter for
high resolu-
tion
measurements and/or a
Mosely Model
680
Strip
Chart Recorder.
External loading
does not affect the
meter accuracy
so
that
both the
meter and dc output
can be used simultaneously.
A
plug for
DC OUT
jack
may
be
purchased under
-hp- Part No. 1251-0067.
3-1