Simpson 270-5, Instruction Manual

Page: 20 / 28

20
c. Set the range switch at one of the four
range positions marked 1 mA, 10 mA,
100 mA, or 500 mA.
d. Turn OFF power. Discharge any ca-
pacitors in circuit.
e. Open the grounded side of the circuit
in which the current is being mea-
sured. Connect the VOM in series with
the circuit. Connect the red test lead
to the positive side and the black test
lead to the negative side.
f. Turn the power on. Read the current
in milliamperes on the black DC scale.
For the 1mA range, use the 0-10 fig-
ures and divide by 10. For the 10mA
range, use the 0-10 figures directly. For
the 100mA range, use the 0-10 fig-
ures and multiply by 10. For the 500mA
range, use the 0-50 figures and multi-
ply by 10.
g. Turn the power off and disconnect the
test leads.
h. Restore circuit to original condition.
4.16 Direct Current Measurement 0-10A Range
The 10A range is not internally fused in the 270.
When using the 10A range, never disconnect a test lead from a jack or from the
circuit while the circuit is energized. Doing so may damage the test jacks or leads
and the arcing may be hazardous to the operator. Turn off circuit power and wait
for the meter reading to drop to zero.
The polarity reversing feature of the function switch does not operate on the 0-
10A range. If polarity is found to be incorrect, turn off circuit power, wait for the
meter indication to read zero and then interchange test lead connections to the
circuit.
a.
Plug the black test lead into the -10A jack and the red test lead into the +10A
jack.
b. Set the range switch at 10 AMPS (dual position with 10mA).
c. Turn the power OFF. Discharge any capacitors in the circuit.
d. Open the ground side of the circuit in which the current is being measured.
Connect the VOM in series with the circuit. Connect the red test lead to the
positive side and the black test lead to the negative side.
NOTE: The function switch has no effect on polarity for the 10 AMPs range.
e. Turn the power on. Read the current directly on the black DC scale. Use the
0-10 figures to read directly in amperes.
f. Turn the power off and disconnect the test leads.
g. Restore circuit to original condition.
+50 AMPS.
250MV.
+10A.
100MA.
10MA.
AMPS
1MA.
ALL TERMINALS 1KV. MAX
270
COMMON
-10A.
-D.C.
+D.C.
500MA.
50V.
AMPS.
WARNING
READ MANUAL BEFORE USE
Figure 4-7. Jacks and Switch
Positions for Measuring Direct
Current