382075 V2.2V 9/10
13
1
φ
3W Power Measurement
1
φ
3W power measurements are similar to 3
φ
3W unbalanced power measurements except
that the nomenclature is different. Two measurements of W
RS
(or W
L1G
) and W
TS
(or
W
L2G
) are required
W
1
φ
W
=
W
RST
=
W
RS
(
L1G
)
+
W
TS
(
L2G
)
1. Measure W
RS
(or W
L1G
).
a. Apply power to the meter with the jaw clear of any conductors
b. Set the rotary switch to the 3
φ
position.
c. Press the 3
φ
button once, and the 3
φ
3W symbol only will appear on the left side of
the LCD. The W
RS
symbol will flash prompting the user to measure W
RS(L1G).
d. If the watt reading is not zero, press the DCA/DCW ZERO button once to zero it.
e. Insert the test leads into the input terminals.
f.
Connect the COM (black) terminal to ground.
g. Connect the V (red) terminal to the second phase (L1).
h. Clamp on to the same phase as connected in step g. (L1).
i.
The power clamp will automatically select the proper range.
j.
Wait until the reading stabilizes, then press the NEXT button. The W
RS
(W
L1G
)
symbol will disappear and the W
RS(L1G)
reading will be stored in memory. The W
T
(W
L2G
) symbol will flash prompting the user to take W
TS
(W
L2G
) measurements.
2. Measure W
TS
(or W
L2G
).
a. Disconnect the test leads from the phase where the jaws were clamped onto in the
previous measurement.
b. Connect the test lead to the L2 line.
d. If the watt reading is not zero, press the DCA/DCW ZERO button once to zero
reading
e. Clamp on to the L2 line where the test lead is connected.
f.
The power clamp will automatically select the proper range.
g. Wait until the reading is stable, then press the NEXT button. The W
T
(or W
L2G
)
symbol will disappear. At this moment, W
TS
(or W
L2G
) is stored in the memory,
3. Once the NEXT button is pressed after measurements of W
RS
(or W
L1G
) and W
TS
(or
W
L2G
) are taken, the power clamp will add the two values together and show the result
on the LCD. The W
RST
symbol will display along with the wattage of the 1
φ
3W
unbalanced Power. PF is not shown in 1
φ
3W unbalanced power mode. See equation
below.
