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Power Monitor


Global Power Monitor for On-panel Installation

Ratings (Power Monitor)

Model KM-N3-FLK
Applicable phase wiring methods Single-phase two-wire, single-phase three-wire, three-phase three-wire,
and three-phase four-wire
Number of measured circuits Single-phase two-wire: 4 circuits max., Single-phase three-wire or three-
phase three-wire: 2 circuits max.,
Three-phase four-wire: 1 circuit
Power supply voltage (operating frequency) 100 to 240 VAC (50/60 Hz)
Power supply allowable voltage range 85% to 110% of rated power supply voltage
Power consumption 7 VA max.
Input Rated input voltages Single-phase, 2-wire: 100 to 277 VAC
Single-phase, 3-wire: 100 to 240 VAC (L-N), 200 to 480 VAC (L-L)
Three-phase, 3-wire: 173 to 277 VAC (L-L)
Three-phase, 4-wire (earthed neutral): 100 to 277 VAC (L-N),
173 to 480 VAC (L-L)
Three-phase, 4-wire (unearthed neutral): 100 to 120 VAC (L-N),
173 to 208 VAC (L-L)
Allowable supply voltage range 85% to 115% of rated power supply voltage
Connectable CTs General-purpose CT with a rated secondary current of 1 A or 5 A *
Maximum CT secondary current 6 A
Rated input frequency 50/60 Hz
Ambient operating temperature -25 to 55°C (with no condensation or icing)
Ambient operating humidity 25% to 85%
Storage temperature -25 to 85°C (with no condensation or icing)
Storage humidity 25% to 85%
Operating altitude 2,000 m max.
Installation environment Overvoltage category II, measurement category II, pollution degree 2
Electromagnetic environment Industrial electromagnetic environment (EN/IEC 61326-1 Table 2)
Compliant standards EN 61010-2-030, EN 61326-1, and UL 61010-1

* The KM-series CTs (the KM20-CTF or KM-NCT Series) cannot be used. Use general-purpose CTs with a secondary-side output of 1 A or 5 A.

Split Type Current Transformer (CT) (CE marking compliant KM-N2/N3 dedicated products *)

Rated primary current: In 100 A 250 A 500 A
Rated secondary current: Is 1 A
Rated frequency 50/60 Hz
Cable Length Please refer to Writing to KM-NCT-E[][][]A
Rated load 1 VA
Insulation resistance 100 MΩ min. (at 500 VDC mega) between core and all output terminals
Dielectric strength voltage 2300 VAC, 1 minute between core and all output terminals.
Weight Approx. 170 g Approx. 175 g Approx. 290 g
Maximum wire diameter 24 dia. 24 dia. 36 dia.
Operating temperature and humidity range -20 to 55 °C, relative humidity: 85% max. with no condensation
Storage temperature and humidity range -30 to 90 °C, relative humidity: 85% max. with no condensation
Applicable standards * EN61010-1, EN61010-2-030, EN61326-1
Installation environment Overvoltage category and measurement category: II, Pollution level: 2

* The KM-NCT-E conforms to the standards shown above ONLY when it is used with a power monitor KM-N2-FLK or KM-N3-FLK to which it is attached. Use of the KM-NCT-E without a power monitor does not conform to these standards.

Wiring to KM-NCT-E[][][]A

• For wiring of the output terminal of CT, use AWG18-14 electric wire (with a cross-section of 0.75-2.0mm2) and Y-shape terminal compatible with the M3 screw.
• The recommended torque for screwing the M3 screws onto the output terminal is 0.3 N·m. Make sure the Y terminal is pushed all the way in and tightened firmly. After fixing the wiring, confirm that the wire is fixed securely.
• The guideline of the maximum wiring length between KM-N2-FLK or KM-N3-FLK and KM-NCT-E is as follows.
The longer the wire length, the larger the measurement error using the KM-NCT-E becomes.
• The limit of the wiring length can also be calculated by the following formula. Calculate the wiring length limit according to the conductor resistivity of the wiring and keep the wiring length below the limit.
• The limits of the wiring length shown below are for reference only. They do not guarantee proper use.

Wiring diameter Guideline for wiring length limit
0.75 mm2 (AWG18 equivalent) 15 m
2.0 mm2 (AWG14 equivalent) 43 m

Wiring extension limit value (one-way) (m)= 0.475/conductor resistivity (Ω/m)

Note: Select a CT cable that does not exceed the rated load of 1 VA.

Performance (Power Monitor)

Model KM-N3-FLK
Measured items Total power consumption (active, regenerative, and reactive), power (active and
reactive), current, voltage, power factor, and frequency
Active power 0.5% (IEC 62053-22 class 0.5S *
Reactive power 2% (IEC 62053-23 class 2) *
Sampling cycle 80 ms for 50 Hz and 66.7 ms for 60 Hz
Insulation resistance (1) Between all electrical circuits and the case: 20 MΩ min. (at 500 VDC)
(2) Between all power supply and voltage inputs and all communications and
pulse output terminals: 20 MΩ max. (at 500 VDC)
Dielectric strength (1) Between all electrical circuits and the case: 1,400 VAC for 1 min
(2) Between all voltage and current inputs and all communications and pulse
output terminals: 1,400 VAC for 1 min
Vibration resistance Single amplitude: 0.1 mm, Acceleration: 15 m/s2, Frequency: 10 to 150 Hz, 10
sweeps for 8 min each along three axes
Shock resistance 150 m/s2, 3 times each in 6 directions (up/down, left/right, forward/backward)
Indications and operation method LCD indications and operation buttons
Weight Approx. 350 g (Power Monitor only)
Degree of protection Front: IP65, Rear case: IP20, Terminal: IP00
Number of outputs Number of outputs: 4 (photoMOS relay outputs)
Used for the total power consumption pulse output.
Output capacity 50 mA at 40 VDC
ON residual voltage: 1.5 V max. (for output current of 50 mA)
OFF leakage current: 0.1 mA max.
Output unit Output unit: 1, 10, 100, 1k, 5k, 10k, 50k, or 100k (wh)
Pulse ON time: 500 ms (Cannot be changed.)
Communications method RS-485 (2-wire half-duplex with start-stop synchronization)
Communications protocol Modbus (RTU): Binary. CompoWay/F: ASCII
Baud rate 1.2, 2.4, 4.8, 9.6, 19.2, or 38.4 kbps
Data length Data length: 7 or 8 bits
Stop bits: 1 or 2 bits
Vertical parity: Even, odd, or none
Maximum transmission
1,200 m
Maximum number of
connected Power
Modbus: 99, CompoWay/F: 31
If you measure more than one circuit with one Power Monitor, the number of
circuits is treated as the number of connected Power Monitors.
Dimensions (H×W×D) 96 × 96 × 64 mm (excluding protrusions)
Installation method On-panel installation
Accessories Instruction Manual and Compliance Sheet, Mounting adapter and waterproof

* The error of the CT or VT is not included. IEC 62053 is an international standard for power metering.