¢ Electrical wiring
• Electricity meter connection composition
To perform energy saving peak cut control, basically, electricity meters with pulse transmission
function measuring all the power consumed by the air conditioner are necessary. Multiple meters
installations are also possible as long as the number of electricity meters is within the specified
limit. A general electricity meter installation configuration is shown below.
Internet
Pulse unit
reference point
measurement
line
measurement
line
Pulse constant
reference point
Pulse constant
reference
point
pulse
transmission
line
Pulse transmission line
CT
VT
(PT)
3ø or 1ø
1ø
VT
(PT)
System controller
Touch panel
controller
System controller
(Remote site)
Transmission line (VRF network)
Outdoor unit
Indoor unit
to CN135
Power cable
Electricity meter
Electricity meter
Locally purchased parts
▪Electricity meter
▪CT
▪VT (PT)
Item Description
Electricity meter
Measures the voltage and current of the power cable to which measurement line is
connected and finds the power consumption from these. In addition, pulses
corresponding to the measured value are output to the transmission line.
Voltage Transformer
(VT)
Transform the power source voltage to a measurable voltage. Transformation ratio is
indicated by VT (PT) ratio. Normally unnecessary for the voltage value level used by
outdoor units and indoor units.
Power Transformer
(PT)
Current Transformer
(CT)
Transform the power line current value to a current measurable by an electricity
meter. Transformation ratio is indicated by CT ratio. There are types which is inserted
between power cables and types which are coupled to the power cables.
Pulse unit
Pulse unit indicates the relationship between electricity meter output pulse and
measured power. The value specified in pulse unit indicates the power in kWh
consumed on the power cable for 1 pulse.
Units: kWh/pulse
The value specified by pulse unit takes into account the VT and CT ratio used and
corresponds to the actual power consumption itself.
Pulse unit reference
point
Indicates the measurement point of the power consumption specified in pulse units.
Pulse constant
Pulse constant indicates the relationship between electricity meter measured power
and output pulses. The value specified by pulse constant indicates how many pulses
are equivalent to 1 kWh of power consumption input to an electricity meter.
Units: pulse/kWh
Because the ratio of VT and CT used is not taken into account in the value specified
by pulse constant, to find the actual power consumption on the power cable, the
pulse constant value must be multiplied by both the VT and CT ratio.
Pulse constant
reference point
Indicates the measurement point of power consumption specified by pulse constant.
• Selection of Electricity meter, CT, and VT
Select the electricity meter, CT, and VT by considering the following items:
– Install electricity meters for each refrigerant system, if circumstances allow.
– Select VT/CT with a small VT/CT ratio.
– When using an electricity meter which is specified in pulse units (kWh/pulse), usually select a
meter with a 1 kWh/pulse output.
2-30. Electricity charge apportionment setting (System controller, Touch panel
controller)
- (07-155) - 2. Function settings
FUNCTION
SETTINGS
FUNCTION
SETTINGS
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