ES-1975 Rev.18

LWT

Power Transducer Series L-UNIT

WATT TRANSDUCER

(with pulse output)
Functions & Features
• Providing a DC output signal and pulse totalizer signal in proportion to AC active power
• Convenient pulse unit output (Wh×10n)
• Measuring bidirectional power flow
• DC output containing little ripple is ideal for computer input
• "Time division multiplication" method accepts distorted waveforms
• Isolation up to 2000 V AC
• High-density mounting
Typical Applications
• Centralized monitoring and control of power management system in a manufacturing facility or building
• SCR – Silicon Controlled Rectifier
 

MODEL: LWT–[1][2][3][4]–[5][6]

ORDERING INFORMATION

• Code number: LWT–[1][2][3][4]-[5][6]
Specify a code from below for each of [1] through [6].
  (e.g. LWT-11A2-C/B/Q)
• Specify the specification for option code /Q
  (e.g. /C01/S01)
• Calibration range (e.g. -750 – +750 W)
• VT ratio, CT ratio (e.g. VT 3300/110 V, CT 250/5 A)
• Special DC output range (For codes Z & 0)
• Pulse output (e.g. 6.666 Wh/pulse)
How To Determine Pulse Unit
[example]
3-phase / 3-wire, VT 3300/110 V, CT 250/5 A,
calibration range 750 W
From Pulse Unit 10 [kWh/pulse]
10 [kWh/pulse] / (3300/110) × (250/5)
= 6.666 × 10–3 [kWh/pulse]
= 6.666 [Wh/pulse]
From Pulse Rate 150 [pulses/kWh]
1 / 150 [pulses/kWh]
= 6.666 × 10–3 [kWh/pulse]
= 6.666 [Wh/pulse]
From Frequency 0.03125 Hz (at 100 %)
750 [W] / 0.03125 [H] × 3600 [s]
= 6.666 [Wh/pulse]

[1] CONFIGURATION

1: 3-phase / 3-wire
2: Single-phase / 2-wire
3: Single-phase / 3-wire
4: 3-phase / 4-wire

[2] INPUT (unbalanced load)

1: 110 V / 5 A AC
2: 110 V / 1 A AC
3: 220 V / 1 A AC
4: 220 V / 5 A AC
5: 220 V / 380 V / 1 A AC (3-phase / 4-wire)
6: 220 V / 380 V / 5 A AC (3-phase / 4-wire)
7: 110 V / 190 V / 1 A AC (3-phase / 4-wire)
8: 110 V / 190 V / 5 A AC (3-phase / 4-wire)
A: 100 V / 200 V / 1 A AC (single-phase / 3- wire)
B: 100 V / 200 V / 5 A AC (single-phase / 3- wire)

[3] DC OUTPUT

Current
A: 4 – 20 mA DC (Load resistance 600 Ω max.)
B: 2 – 10 mA  DC (Load resistance 1200 Ω max.)
C: 1 – 5 mA DC (Load resistance 2400 Ω max.)
D: 0 – 20 mA DC (Load resistance 600 Ω max.)
E: 0 – 16 mA DC (Load resistance 750 Ω max.)
F: 0 – 10 mA DC (Load resistance 1200 Ω max.)
G: 0 – 1 mA DC (Load resistance 12 kΩ max.)
J: 0 – 5 mA DC (Load resistance 2400 Ω max.)
FW: -10 – +10 mA DC (Load resistance 1000 Ω max.)
GW: -1 – +1 mA DC (Load resistance 10 kΩ max.)
JW: -5 – +5 mA DC (Load resistance 2000 Ω max.)
Z: Specify current (See OUTPUT SPECIFICATIONS)
Voltage
1: 0 – 10 mV DC (Load resistance 10 kΩ min.)
2: 0 – 100 mV DC (Load resistance 100 kΩ min.)
3: 0 – 1 V DC (Load resistance 1000 Ω min.)
4: 0 – 10 V DC (Load resistance 10 kΩ min.)
5: 0 – 5 V DC (Load resistance 5000 Ω min.)
6: 1 – 5 V DC (Load resistance 5000 Ω min.)
1W: -10 – +10 mV DC (Load resistance 10 kΩ min.)
2W: -100 – +100 mV DC (Load resistance 100 kΩ min.)
3W: -1 – +1 V DC (Load resistance 1000 Ω min.)
4W: -10 – +10 V DC (Load resistance 10 kΩ min.)
5W: -5 – +5 V DC (Load resistance 5000 Ω min.)
0: Specify voltage (See OUTPUT SPECIFICATIONS)

[4] PULSE OUTPUT (open collector)

0: None
1: 2.777 Hz at 100 % input
2: Specify pulse unit (within 0.006 – 3.12 Hz)

[5] AUXILIARY POWER SUPPLY

AC Power
B: 100 V AC
C: 110 V AC
D: 115 V AC
F: 120 V AC
G: 200 V AC
H: 220 V AC
J: 240 V AC
DC Power
R: 24 V DC
V: 48 V DC
P: 110 V DC

[6] OPTIONS (multiple selections)

Optional Process
blank: None
/B: Bonding
Other Options
blank: none
/Q: Option other than the above (specify the specification)

SPECIFICATIONS OF OPTION: Q (multiple selections)

COATING (For the detail, refer to our web site.)
/C01: Silicone coating
/C02: Polyurethane coating
/C03: Rubber coating
TERMINAL SCREW MATERIAL
/S01: Stainless steel

GENERAL SPECIFICATIONS

Construction: Stand-alone; terminal access at the front
Connection: M3.5 screw terminals (torque 0.8 N·m)
Screw terminal: Nickel-plated steel (standard) or stainless steel
Housing material: Flame-resistant resin (black)
Isolation: Voltage input to current input to DC output to pulse output to auxiliary power
Computation: Time division multiplication
Overrange output: Approx. -10 – +120 % at 1 – 5 V
Zero adjustment(DC output): -5 to + 5 % (front)
Span adjustment(DC output): 95 to + 105 % (front)

INPUT SPECIFICATIONS

Frequency: 50 or 60 Hz
• Voltage Input
Operational range: 0 – 120 % of rating
Overload capacity: 150 % of rating for 10 sec., 120 % continuous
• Current Input
Operational range: 0 – 120 % of rating
Overload capacity: 1000 % of rating for 3 sec., 200 % for 10 sec., 120% continuous
How to determine Wattage Range
Calibration Range [W] = Measuring Wattage ÷ ((VT Ratio) × (CT Ratio))
Check that the required calibration range is within the available range in the table. Specify this range when ordering.
[Example]
3-phase / 3-wire, measuring wattage 750 kW,
VT 3300/110 V, CT 250/5 A
750 × 103 [W] ÷ ((3300÷110) × (250÷5)) = 500 [W]

OUTPUT SPECIFICATIONS

DC Output
DC Current: -10 – + 20 mA DC
Span: Min. 1 mA, max. 20 mA
Offset: Max. 1.5 times span
Load resistance: Output drive 12 V maximum; 10 V for [±] output
DC Voltage: -10 – +12 V DC
Minimum span: 5 mV
Offset: Max. 1.5 times span
Load resistance: Output drive 1 mA max. at ≥ 0.5 V
Pulse output: Open collector; 0 Hz at 0 W
(cutout at approx. 0.5 – 1.0 %)
Rating: 35 V DC @ 100 mA
ON voltage: ≤ 1 V at 100 mA
ON duration: Max. 0.5 sec., min. approx. 50 msec.
Frequency range:
0 – 2.777 Hz (0 – 100 %) standard; 0 – 0.006 Hz through 3.12 Hz is possible.
2.777 Hz at 100 % Input
[example] 1000 W calibration range
2.777 [Hz] × 3600 [s] / 1 [kW] = 10000 [pulses/kWh]
Specified Pulse Unit: Refers to how much electrical energy (kWh) consumption at the primary of the VT and CT corresponds to the single output pulse per hour from the transducer.
Output Frequeny [Hz] = Calibration Range [kW] × VT Ratio × CT Ratio / Pulse Unit [kWh/pulse] × 3600 [s]

INSTALLATION

Auxiliary power supply
AC: Operational voltage range: rating -15/+10 %,
50/60 Hz, approx. 2 VA
DC: Operational voltage range: rating ±10 %,
or 85 – 150 V for 110 V rating, ripple 10 %p-p max.,
approx. 2 W (18 mA at 110 V)
Operating temperature: -10 to +55°C (14 to 131°F)
Operating humidity: 30 to 85 %RH (non-condensing)
Mounting: Surface or DIN rail
Weight: 450 g (0.99 lb)

PERFORMANCE in percentage of span

Accuracy: ±0.5 % (at 23°C ±10°C or 73.4°F ±18°F,
45 – 65 Hz)
Response time: ≤ 2 sec. (0 – 100 % ±1 %)
Ripple: 0.5 %p-p max.(The output ripple may increase when there is great difference between the frequencies of input signal and power supply)
Line voltage effect: ±0.1 % over voltage range
Insulation resistance: ≥ 100 MΩ with 500 V DC
Dielectric strength: 2000 V AC @ 1 minute
(voltage input to current input to DC output to pulse output to auxiliary power to ground)
Impulse withstand voltage: 1.2 / 50 μsec., ±5 kV
(input to output or ground)

CONNECTION DIAGRAM

EXTERNAL DIMENSIONS & TERMINAL ASSIGNMENTS unit: mm [inch]

MOUNTING REQUIREMENTS unit: mm [inch]

EXPLANATIONS OF TERMS

• Bonding
An silicone adhesive reinforces the part, which is sensitive to vibration, on PWB. The improvement of vibration performance is not assured.