·Some details are not shown. Please refer to specification sheets for all information.

LTWT

Power Transducer Series LT-UNIT

WATT TRANSDUCER

Functions & Features
• Provides a DC output signal and a 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
• Conforms to IEC 60688
Typical Applications
• Centralized monitoring and control of power management system in a manufacturing facility or building
• SCR – Silicon Controlled Rectifier
 

MODEL: LTWT–[1][2][3][4][5]–[6][7]

ORDERING INFORMATION
• Code number: LTWT–[1][2][3][4][5]–[6][7]
Specify a code from below for each [1] through [7].
  (e.g. LTWT-115A2-R/T/Q)
• Specify the specification for option code /Q
  (e.g. /C01)
Use Ordering Information Sheet (No. ESU-3355).
• Special output range (For codes Z & 0)

How to determine Pulse Unit
[Example]
3-phase / 3-wire, VT 3300/110 V, CT 250/5 A,
calibration range 750 W
10 [kWh/pulse] ÷ ((3300÷110) × (250÷5))
= 6.666 × 10–3 [kWh/pulse]
= 6.666 [Wh/pulse]
Check that the required pulse unit is within the available frequency range, 0.006 – 3.12 Hz.
Input Range [W] ÷ (Calculated Pulse × 3600 [s])
= 750 ÷ (6.666 × 3600)
= 0.03125 [Hz]

[1] CONFIGURATION
1: 3-phase / 3-wire
2: Single-phase / 2-wire
3: Single-phase / 3-wire
4: 3-phase / 4-wire

[2] VT INPUT (unbalanced load)
For 3-phase / 4-wire, phase voltages (e.g. 110 V / √3 ) are used.
1: 100, 110, 115, 120 V AC
(Not selectable for single-phase / 3-wire system.)
2: 190, 200, 210, 220, 230, 240 V AC
(Not selectable for single-phase / 3-wire system.)
4: 380, 400, 415, 430, 440, 480 V AC
(Not selectable for single-phase / 3-wire system.)
A: 100 V / 200 V AC
(single-phase / 3-wire only)

[3] CT INPUT (unbalanced load)
Current
1: 1 A AC
2: 2 A AC
5: 5 A AC

[4] DC OUTPUT
Current
A: 4 – 20 mA DC (Load resistance 500 Ω max.)
D: 0 – 20 mA DC(Load resistance 500 Ω max.)
F: 0 – 10 mA DC (Load resistance 1000 Ω max.)
G: 0 – 1 mA DC (Load resistance 10 kΩ max.)
J: 0 – 5 mA DC (Load resistance 2000 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)

[5] PULSE OUTPUT (open collector)
0: None
1: 2.777 Hz at 100 % input
2: Specify pulse unit (within 0.006 – 3.12 Hz)

[6] AUXILIARY POWER SUPPLY
AC Power
K3: 100 – 120V AC
(Operational voltage range 85 - 132 V, 47 - 66 Hz)
L3: 200 – 240V AC
(Operational voltage range 170 - 264 V, 47 - 66 Hz)
DC Power
R: 24 V DC
(Operational voltage range 24 V ±10 %, ripple 10 %p-p max.)
V: 48 V DC
(Operational voltage range 48 V ± 10 % , ripple 10 % p-p max.)
P: 110 V DC
(Operational voltage range 85 – 150 V, ripple 10 %p-p max.)
(CE not available)

[7] OPTIONS (multiple selections)
Terminal Cover
blank: Without
/T: With
Custom specification
(Refer to the custom specification list for difference
of specification and combination of code numbers.)
blank: none
/X1: Input range
/X2: Input span
Other Options
blank: none
/Q: Option other than the above (specify the specification)

SPECIFICATIONS OF OPTION: Q
COATING (For the detail, refer to M-System's web site.)
/C01: Silicone coating
/C02: Polyurethane coating
/C03: Rubber coating

GENERAL SPECIFICATIONS
Connection: M4 screw terminals (torque 1.2 N·m)
Screw terminal: Chrome-plated 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 to +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: 200 % of rating for 10 sec., 120 % continuous
• Current input
Operational range: 0 – 120 % of rating
Overload capacity: 4000 % of rating for 1 sec., 2000 % for 4 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 Current: -10 – +20 mA DC
Span: Min. 1 mA, max. 20 mA
Offset: Max. 1.5 times span
Load resistance: Output drive 10 V max.
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. 50 msec. (approx.)
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.

INSTALLATION
Power Consumption
AC:  Approx. 2 VA
DC: 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)
Magnetic field (ext. origin) effect: ± 0.5 % (400 A/m)
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: ±0.25 % over operational voltage range (Operational voltage range is [K3: 90 to 132 V AC], [L3: 180 to 264 V AC] when the DC output code is 4W or the specified voltage is ≤ -9 V)
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)

STANDARDS & APPROVALS
EU conformity:
EMC Directive 
  EMI EN 61000-6-4
  EMS EN 61000-6-2
Low Voltage Directive 
 EN 61010-1
 Measurement Category II (input, output)
 Installation Category II (auxiliary power)
 Pollution Degree 2
 Input to output or auxiliary power: Reinforced insulation (550 V)
 Output to auxiliary power: Reinforced insulation (300 V)
RoHS Directive
  EN 50581

CONNECTION DIAGRAM

EXTERNAL DIMENSIONS & TERMINAL ASSIGNMENTS unit: mm (inch)

M-System Co., Ltd.