3-20
IM 253710-01E
Note
•
Check that the power measurement modules are installed in order starting from the element
number 1 slot. If you leave the slots that have smaller element numbers empty,
measurements will not be made properly. (For example, do not install a power
measurement module into the element number 2 slot and leave the element number 1 slot
empty. Do not install power measurement modules into element number 1 and 3 slots and
leave the element number 2 slot empty.) For the procedures on installing the modules, see
section 3.3, “Installing the Input Module.”
•
When the sensor input module is installed into the element number 4 slot, only up to three
power measurement modules can be installed. In this case, you cannot select a wiring
method that uses four power measurement modules.
•
After wiring, the wiring method must be selected. See section 5.2, “Selecting the Wiring
Method.”
•
The thick lines on the wiring diagrams indicate areas of current flow. Use wires that are
suitable for the current present.
•
The scaling function can be used to transform the input signal to data that correspond to
direct measurements. For the procedures, see section 5.5, “Setting the Scaling Function
when using an External PT or CT.”
•
Note that the frequency and phase characteristics of the PT or CT affect the measured data.
•
To measure the apparent power and power factor more accurately when measuring the
power of an unbalanced three-phase circuit, it is recommended that a three-voltage, three-
current (3V3A) system be used to make the measurement.
•
In 3P3W and 3V3A systems, the wiring system may be different between the PZ4000 and
another product (another digital power meter) due to the differences in the input element
that is wired. To achieve correct measurements, check the wiring system.
•
For safety reasons, this section indicates wiring diagrams in which the common terminals
(+/-) of the secondary side of the PT or CT are grounded. However, the necessity of
grounding and the grounding location (ground near the PT or CT or ground near the power
meter) vary depending on the object being measured.
For the combinations of the elements and the input terminals in the figures below, see
“Wiring Examples” in section 3.7, “Directly Wiring the Circuit under Measurement.”
Wiring Example of a single-phase, two-wire system (1P2W) using PT and CT
SOURCE
LOAD
L CT
PT
V
v
l
SOURCE
LOAD
L CT
PT
V
v
l
±
Input terminal
I
U
±
±
Input terminal
I
U
±
Wiring Example of a single-phase, three-wire system (1P3W) using PT and CT
L CT
PT
V
v
l
L CT
PT
V
v
l
SOURCE
LOAD
N
±
Input terminal 1
I
U
±
±
Input terminal 2
I
U
±
3.9 Using an External PT or CT to Wire the Circuit under Measurement
