Fujitsu AIRSTAGE J-II Design & Technical Manual page 681

ELECTRICAL WIRING
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Electricity meter connection composition
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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.
Electricity meter
Pulse constant
reference point
VT
(PT)
3ø
1ø
Pulse unit
VT
reference point
(PT)
Pulse constant
reference
point
Electricity meter
Item
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.
VT(PT) Voltage Transformer (Power Transformer)
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.
CT Current Transformer
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 Indicates the measurement point of the power consumption specified in pulse
point 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 1kWh 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 Indicates the measurement point of power consumption specified by pulse
reference point constant.
pulse
transmission
line
to CN135
measurement
line
Outdoor unit
CT
Power cable
Indoor unit
measurement
line
RB unit
Transmission line (VRF Network)
Description
- (07-155) -
System Controller
Internet
System Controller
to CN135
(Remote site)
pulse transmission line
Field supplied parts
▪Electricity meter
▪CT
▪VT (PT)
Remarks