Radio Shack 22-174A - Measuring 3-Phase AC Voltages; Safety and Calculation for 3-Phase; Measuring AC;DC Current; Current Measurement Safety and Setup

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Warning:
NEVER
TRY TO
MEASURE
AN AC
VOTTAGE
THAT
IS RIDING
ON A
DC VOLTAGE
LEVEL
WHERE
THE
PEAK
AC VOLTAGE
EXCEEDS
1OOOV
WITH
RESPECT
TO
EARTH
GROUND.
MEASURING
SPHASE
AC VOLTAGES
We
designed this
meter
to
measure
household
AC
voltage.
lt is
not for
commercial
or industdd
use. lf
you
want
to
measure
3-
phase,
lin+'to-line
voltages,
please
note
the following:
e
Because
of the
dangers inherent
when
you
measure
three.
phase
circuits, we
strongly recommend
you
do
not
use
this
meter for
such applications.
o
Do not
exceed the maximum
RMS AC rating
(750
VAC).
o
lf
you
choose to make
the measurements,
use extreme
caution. The highest
possible
voltage is
much
greater
than
the voltage
between
any
point
in the
circuit and
ground.
To
determine lineto-line
voltage,
measure
between
the circuit
and a known
ground
point.
Then
multiply
the result
by
1.732.
For
gxample,
if
you
measure
a voltage
of 462 volts
between
a
point
in
the circuit
and
ground,
the
possible
line-to-line
voltage
is 800 volts.
462 Volts
x 1.732
=
800 Volts
This
voltage
exceeds the meter's
range
and
you
should
not
connect the meter
to the
circuit or to any
equipment
connected
to
the circuit. Doing
so could
present
a dangerous
shock haz-
ard and damage
the meter.
22
MEASURING
AC/DC
CURRENT
To
measure
current,
break
the circuit
and connect
the
leads
in
series
with
the
circuit. Never
connect
the
leads
across a volt-
age
source
(in
parallel).
Doing
so can
blow the
fuse
or
damage
the
circuit under
test. The maximum
current input
limit is 10A-
WARNINGS:
DO NOT
APPLY VOLTAGE
DIRECTLY
ACROSS
THE IN-
PUT
TERMINALS
WHILE IN
THE
CURRENT MODE. YOU
MUST
CONNECT THE METER
IN
SERIES WITH THE
ctRcurT.
THE 1OA
INPUT
TERMINAL IS NOT
FUSED. A
SEVERE
FIRE
HMARD
AND
SHORT CIRCUIT DANGER
EXIST IF
YOU
APPLY A
VOUTAGE WITH HIGH
CURRENT
CAPA-
BILITIES
TO THIS
TERMINAL. YOU
ALSO COULME-
STROYTHE
METER.
23
Set the function
controlto
A
or
A
. nA
appears on
the display.
2.
Set the
current switch for
the
desired current range.
Note: To
measure
a
current level
that exceeds
0.4
amps,
you
must
use
the 10A input.