13
Connecting to Multiple Single-phase Loads
Figure 4 presents a means to monitor 3 single-phase loads
simultaneously. The loads must all share the same neutral voltage
connection. If the loads run off the same line voltage, connect V
1
, V
2
,
and V
3
to the same "hot" wire. I
1
, I
2
, and I
3
serve the 3 loads. This
approach can also be used to evaluate the current of a 4th load, but
the power used by that load will not be calculated.
In this configuration, the voltage, current, and power of each load can
be displayed directly or graphed on your PC using our PSM software.
Connecting to Split-Phase (Two Phase) Power
Fig 5 shows the recommended connections to a split-phase system as found in commercial and
residential facilities, when measuring the supply to two single phase loads. There are two "Hot" wires
180 degrees out of phase with each other and sharing the same neutral.
Appliances such as ovens that require 240V will span across both hot
wires. When evaluating the power for a load spanning the two phases,
remove the V
N
voltage lead since it may affect the power factor readings
of each phase.
In this configuration, a reading of V
1N
is of hot-neutral and V
2N
is hot2-
neutral. I
N
does not need to be connected and V
N
should not be
connected when the load spans the two phases. The power associated
with one hot is measured as phase 1, the power of the other hot is
measured as phase 2. In phase-neutral measurement mode, the voltage
readings will be from hot-to-neutral. If you change the measurement
mode to phase-phase, V
12
will be the hot-to-hot voltage that serves the
high power appliance.
Connecting to Three-Phase Four-Wire (Wye) Power
Figure 6 presents the recommended connections to a three-phase
system with voltages referenced to neutral, a "phase-neutral"
or “three-
phase four-
wire wye” configuration.
Be sure to follow the safety warnings of the previous sections
before making the connections.
Although the current of each phase is carried by neutral, neutral current
is generally relatively small since the currents of the 3 phases largely
cancel each other in the neutral leg. In a perfectly balanced system the
current in neutral would be zero.
In a wye system, each phase is essentially independent of each other.
For this reason, the power factor of each phase has direct meaning, but
the total power factor is less meaningful. Most commercial wiring and
newer industrial wiring is in this wye configuration.
ATPOL II
ATPOL II
ATPOL II
Содержание ATPOL II
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