Current Transducer LESR series
IP N = 6, 15, 25, 50 A
Ref: LESR 6-NP, LESR 15-NP, LESR 25-NP, LESR 50-NP
For the electronic measurement of current: DC, AC, pulsed..., with galvanic separation between
the primary and the secondary circuit.
Features
Applications
●● Closed loop multi-range current transducer
●● AC variable speed and servo motor drives
●● Voltage output
●● Static converters for DC motor drives
●● Unipolar supply voltage
●● Battery supplied applications
●● Compact design for PCB mounting.
●● Uninterruptible Power Supplies (UPS)
Advantages
●● Very low offset drift
●● Very good dv/dt immunity
●● Switched Mode Power Supplies (SMPS)
●● Power supplies for welding applications
●● Solar inverters.
●● CASR footprint compatible
Standards
●● Reference pin with two modes: Ref IN and Ref OUT
●● IEC 61800-1: 1997
●● Extended measuring range for unipolar measurement.
●● IEC 61800-2: 2015
●● IEC 61800-3: 2004
●● IEC 61800-5-1: 2007
●● IEC 62109-1: 2010
●● IEC 62477-1: 2012
●● UL 508:2013.
Application Domain
●● Industrial.
N°97.O8.09.000.0, N°97.O8.15.000.0, N°97.O8.19.000.0, N°97.O8.25.000.0
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LESR series
Absolute maximum ratings
Parameter
Symbol
Unit
Value
Maximum supply voltage
UC max
V
7
Maximum primary conductor temperature
TB max
°C
110
Maximum primary current
IP max
A
20 × IPN
UESD max
kV
4
Maximum electrostatic discharge voltage
Stresses above these ratings may cause permanent damage. Exposure to absolute maximum ratings for extended periods may
degrade reliability.
UL 508: Ratings and assumptions of certification
File # E189713 Volume: 2 Section: 11
Standards
●● CSA C22.2 NO. 14-10 INDUSTRIAL CONTROL EQUIPMENT - Date 2011/08/01
●● UL 508 STANDARD FOR INDUSTRIAL CONTROL EQUIPMENT - Date 2013
Ratings
Parameter
Symbol
Primary involved potential
Unit
Value
V AC/DC
600
Max surrounding air temperature
TA
°C
105
Primary current
IP
A
According to series primary
currents
Secondary supply voltage
UC
V DC
7
Output voltage
Vout
V
0 to 5
Conditions of acceptability
When installed in the end-use equipment, consideration shall be given to the following:
1 - These devices must be mounted in a suitable end-use enclosure.
2-T
he terminals have not been evaluated for field wiring.
3 - The LES, LESR, LKSR, LPSR, LXS and LXSR Series shall be used in a pollution degree 2 environment or better.
4-L
ow voltage circuits are intended to be powered by a circuit derived from an isolating source (such as a transformer, optical
isolator, limiting impedance or electro-mechanical relay) and having no direct connection back to the primary circuit (other than
through the grounding means).
5-T
hese devices are intended to be mounted on the printed wiring board of the end-use equipment (with a minimum CTI of 100).
6-L
ES, LESR, LKSR and LPSR Series: based on results of temperature tests, in the end-use application, a maximum of 110°C
cannot be exceeded on the primary jumper.
Marking
Only those products bearing the UL or UR Mark should be considered to be Listed or Recognized and covered under UL’s FollowUp Service. Always look for the Mark on the product.
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LESR series
Insulation coordination
Parameter
Symbol
Unit
Value
RMS voltage for AC insulation test, 50 Hz, 1 min
Ud
kV
4.3
Impulse withstand voltage 1.2/50 μs
ÛW
kV
8
Insulation resistance
RINS
GΩ
18
Partial discharge RMS test voltage (qm < 10 pC)
Ut
kV
1.65
Clearance (pri. - sec.)
dCI
Creepage distance (pri. - sec.)
dCp
Case material
-
measured at 500 V DC
See dimensions drawing on
page 19
mm
-
CTI
Comparative tracking index
Comment
V0 according
to UL 94
600
Application example
V
300 V
CAT III, PD2
Reinforced insulation, non
uniform field according to
IEC 61800-5-1
Application example
V
600 V
CAT III, PD2
Basic insulation, non
uniform field according to
IEC 61800-5-1
Environmental and mechanical characteristics
Parameter
Symbol
Unit
Min
Ambient operating temperature
TA
°C
−40
105
Ambient storage temperature
TS
°C
−55
125
Mass
m
g
Typ
Max
Comment
10
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LESR series
Electrical data LESR 6-NP
At TA = 25 °C, UC = +5 V, NP = 1 turn, RL = 10 kΩ internal reference, unless otherwise noted (see Definition of typical, minimum and
maximum values paragraph in page 18).
Parameter
Symbol
Unit
Primary nominal RMS current
IP N
A
Primary current, measuring range
IP M
A
Number of primary turns
NP
Supply voltage
UC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
Vref
V
2.485
External reference voltage
Vref
V
0.5
Output voltage
Vout
V
0.25
Output voltage @ IP = 0 A
Vout
V
Electrical offset voltage
VO E
mV
−5
5
100 % tested Vout − Vref
Electrical offset current
referred to primary
IO E
mA
−48
48
100 % tested
Temperature coefficient of Vref
@ IP = 0 A
TCVref
ppm/K
±70
Internal reference
Temperature coefficient of Vout
@ IP = 0 A
TCVout
ppm/K
±14
ppm/K of 2.5 V
−40 °C … 105 °C
Theoretical sensitivity
Gth
mV/A
Sensitivity error
εG
%
TCG
ppm/K
εL
% of IP N
−0.1
0.1
Magnetic offset current (10 × IP N)
referred to primary
IO M
mA
−25
25
Output RMS voltage noise spectral
density 100 … 100 kHz referred to
primary
eno
µV/Hz½
Output voltage noise
DC … 10 kHz
DC … 100 kHz
DC … 1 MHz
Vno
mVpp
Reaction time @ 10 % of IP N
tra
µs
0.3
RL = 1 kΩ, di/dt = 50 A/µs
Step response time to 90 %
of IP N
tr
µs
0.4
RL = 1 kΩ, di/dt = 50 A/µs
Frequency bandwidth (±1 dB)
BW
kHz
Overall accuracy
XG
% of IP N
1.25
Overall accuracy @ TA = 85 °C
(105 °C)
XG
% of IP N
1.25 (1.5)
Accuracy
X
% of IP N
0.5
Accuracy @ TA = 85 °C (105 °C)
X
% of IP N
0.75 (1)
Temperature coefficient of G
Linearity error
Min
Typ
Max
Comment
Apply derating according
to fig. 21
6
−20
20
1, 2, 3
4.75
5
17 +
5.25
I (mA)
N
P
S
2.5
20 +
I (mA)
N
P
S
2.515
NS = 2000 turns
Internal reference
2.75
4.75
with UC = +5 V
Vref
104.2
−0.2
625 mVIP N
0.2
100 % tested
±40
−40 °C … 105 °C
7
10.5
13.4
13.6
300
RL = 1 kΩ
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LESR series
Electrical data LESR 15-NP
At TA = 25 °C, UC = +5 V, NP = 1 turn, RL = 10 kΩ internal reference, unless otherwise noted (see Definition of typical, minimum and
maximum values paragraph in page 18).
Parameter
Symbol
Unit
Min
Primary nominal RMS current
IP N
A
Primary current, measuring range
IP M
A
Number of primary turns
NP
Supply voltage
UC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
Vref
V
2.485
External reference voltage
Vref
V
0.5
2.75
Output voltage
Vout
V
0.25
4.75
with UC = +5 V
100 % tested Vout − Vref
Typ
Max
Comment
Apply derating according
to fig. 22
15
−51
51
1, 2, 3
4.75
5
17 +
5.25
I (mA)
N
P
S
2.5
20 +
I (mA)
N
P
S
2.515
NS = 2000 turns
Internal reference
Output voltage @ IP = 0 A
Vout
V
Electrical offset voltage
VO E
mV
−1.75
1.75
Electrical offset current
referred to primary
IO E
mA
−42
42
100 % tested
Temperature coefficient of Vref
@ IP = 0 A
TCVref
ppm/K
±70
Internal reference
Temperature coefficient of Vout
@ IP = 0 A
TCVout
ppm/K
±6
ppm/K of 2.5 V
−40 °C … 105 °C
Theoretical sensitivity
Gth
mV/A
Sensitivity error
εG
%
TCG
ppm/K
εL
% of IP N
Temperature coefficient of G
Linearity error
Vref
41.67
−0.2
625 mVIP N
0.2
100 % tested
±40
−40 °C … 105 °C
−0.1
0.1
−45
45
Magnetic offset current (10 × IP N)
referred to primary
IO M
Output RMS voltage noise spectral
density 100 … 100 kHz referred to
primary
eno
µV/Hz½
Output voltage noise
DC … 10 kHz
DC … 100 kHz
DC … 1 MHz
Vno
mVpp
Reaction time @ 10 % of IP N
tra
µs
0.3
RL = 1 kΩ, di/dt = 50 A/µs
Step response time to 90 %
of IP N
tr
µs
0.4
RL = 1 kΩ, di/dt = 50 A/µs
Frequency bandwidth (±3 dB)
BW
kHz
Overall accuracy
XG
% of IP N
0.75
Overall accuracy @ TA = 85 °C
(105 °C)
XG
% of IP N
0.75 (1)
Accuracy
X
% of IP N
0.5
Accuracy @ TA = 85 °C (105 °C)
X
% of IP N
0.65 (0.75)
3.5
4.5
5.7
6.3
300
RL = 1 kΩ
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LESR series
Electrical data LESR 25-NP
At TA = 25 °C, UC = +5 V, NP = 1 turn, RL = 10 kΩ internal reference, unless otherwise noted (see Definition of typical, minimum and
maximum values paragraph in page 18).
Parameter
Symbol
Unit
Min
Primary nominal RMS current
IP N
A
Primary current, measuring range
IP M
A
Number of primary turns
NP
Supply voltage
UC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
Vref
V
2.485
External reference voltage
Vref
V
0.5
2.75
Output voltage
Vout
V
0.25
4.75
Typ
Max
Comment
Apply derating according
to fig. 23
25
−85
85
1, 2, 3
4.75
5
17 +
5.25
I (mA)
N
P
S
2.5
20 +
I (mA)
N
P
S
2.515
NS = 2000 turns
Internal reference
with UC = +5 V
Output voltage @ IP = 0 A
Vout
V
Electrical offset voltage
VO E
mV
−1
1
100 % tested Vout − Vref
Electrical offset current
referred to primary
IO E
mA
−40
40
100 % tested
Temperature coefficient of Vref
@ IP = 0 A
TCVref
ppm/K
±70
Internal reference
Temperature coefficient of Vout
@ IP = 0 A
TCVout
ppm/K
±4
ppm/K of 2.5 V
−40 °C … 105 °C
Theoretical sensitivity
Gth
mV/A
Sensitivity error
εG
%
TCG
ppm/K
Temperature coefficient of G
Linearity error
Vref
25
−0.2
625 mVIP N
0.2
100 % tested
±40
−40 °C … 105 °C
εL
% of IP N
−0.1
0.1
Magnetic offset current (10 × IP N)
referred to primary
IO M
mA
−60
60
Output RMS voltage noise spectral
density 100 … 100 kHz referred to
primary
eno
µV/Hz½
Output voltage noise
DC … 10 kHz
DC … 100 kHz
DC … 1 MHz
Vno
mVpp
Reaction time @ 10 % of IP N
tra
µs
0.3
RL = 1 kΩ, di/dt = 50 A/µs
Step response time to 90 %
of IP N
tr
µs
0.4
RL = 1 kΩ, di/dt = 50 A/µs
Frequency bandwidth (±3 dB)
BW
kHz
Overall accuracy
XG
% of IP N
0.8
Overall accuracy @ TA = 85 °C
(105 °C)
XG
% of IP N
0.85 (0.9)
Accuracy
X
% of IP N
0.5
Accuracy @ TA = 85 °C (105 °C)
X
% of IP N
0.65 (0.75)
1.8
2.6
3.9
5.1
300
RL = 1 kΩ
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LESR series
Electrical data LESR 50-NP
At TA = 25 °C, UC = +5 V, NP = 1 turn, RL = 10 kΩ internal reference, unless otherwise noted (see Definition of typical, minimum and
maximum values paragraph in page 18).
Parameter
Symbol
Unit
Primary nominal RMS current
IP N
A
Primary current, measuring range
IP M
A
Number of primary turns
NP
Supply voltage
UC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
Vref
V
2.485
External reference voltage
Vref
V
0.5
Output voltage
Vout
V
0.25
Output voltage @ IP = 0 A
Vout
V
Electrical offset voltage
VO E
mV
Electrical offset current
referred to primary
IO E
mA
Temperature coefficient of Vref
@ IP = 0 A
TCVref
Temperature coefficient of Vout
@ IP = 0 A
Theoretical sensitivity
Sensitivity error
Min
Typ
Max
Comment
Apply derating according
to fig. 24
50
−150
150
1, 2, 3
4.75
5
17 +
5.25
I (mA)
N
P
S
2.5
20 +
I (mA)
N
P
S
2.515
NS = 1600 turns
Internal reference
2.75
4.75
with UC = +5 V
−0.7
0.7
100 % tested Vout − Vref
−56
56
100 % tested
ppm/K
±70
Internal reference
TCVout
ppm/K
±3
ppm/K of 2.5 V
−40 °C … 105 °C
Gth
mV/A
εG
%
Vref
12.5
−0.2
625 mVIP N
0.2
100 % tested
±40
−40 °C … 105 °C
TCG
ppm/K
εL
% of IP N
−0.1
0.1
Magnetic offset current (10 × IP N)
referred to primary
IO M
mA
−60
60
Output RMS voltage noise spectral
density 100 … 100 kHz referred to
primary
eno
µV/Hz½
Output voltage noise
DC … 10 kHz
DC … 100 kHz
DC … 1 MHz
Vno
mVpp
Reaction time @ 10 % of IP N
tra
µs
0.3
RL = 1 kΩ, di/dt = 50 A/µs
Step response time to 90 %
of IP N
tr
µs
0.4
RL = 1 kΩ, di/dt = 50 A/µs
Frequency bandwidth (±3 dB)
BW
kHz
Overall accuracy
XG
% of IP N
0.7
Overall accuracy @ TA = 85 °C
(105 °C)
XG
% of IP N
0.7 (0.8)
Accuracy
X
% of IP N
0.5
Accuracy @ TA = 85 °C (105 °C)
X
% of IP N
0.65 (0.75)
Temperature coefficient of G
Linearity error
1.7
2.4
3.2
4.8
300
RL = 1 kΩ
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LESR series
Typical performance characteristics LESR 6-NP
0.1
4
Rel. Sensitivity 20
Phase
2
10
0
0
0
−0.05
−0.1
−6
−2
−10
−4
−20
−6
−30
−8
−40
−10
1
10
6
I [A]
Phase [°]
Relative Sensitivity [dB]
Linearity Error [ % IP N ]
0.05
2
3
10
P
Figure 1: Linearity error
4
−50
6
10
5
10
10
Frequency [Hz]
10
Figure 2: Frequency response
6
0.625
0.417
Vout−Vref (V)
4
IP (A)
IP
Vout−Vref
2
0.208
0
0
100
200
300
t (µs)
400
500
Figure 3: Step response
10000
3.5
3.4
600
1000
3.3
100
10
3.1
400
VP
Vout
Vref
200
3.0
2.9
Vout (V)
Primary Voltage VP (V)
eno (µVRMS/ Hz1/2 )
3.2
2.8
2.7
2.6
1
2.5
1
10
2
10
3
10
4
10
fc (Hz)
5
10
Figure 4: Output noise voltage spectral density
6
10
7
10
2.4
20 kV/µs
0
0
1
2
3
t (µs)
4
5
6
2.3
7
2.2
8
Figure 5: dv/dt
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LESR series
Typical performance characteristics LESR 15-NP
0.1
0
−0.05
−0.1
−15
2
10
0
0
−2
−10
−4
−20
−6
−30
−8
−40
−10
1
10
15
I [A]
Rel. Sensitivity 20
Phase
Phase [°]
Relative Sensitivity [dB]
Linearity Error [ % IP N ]
0.05
4
2
3
10
Figure 6: Linearity error
4
−50
6
10
5
10
10
Frequency [Hz]
P
10
Figure 7: Frequency response
15
0.625
0.417
Vout−Vref (V)
10
IP (A)
IP
Vout−Vref
5
0.208
0
0
100
200
300
t (µs)
400
500
Figure 8: Step response
3.5
10000
3.4
600
3.3
3.2
100
10
3.1
400
VP
Vout
Vref
200
3.0
2.9
Vout (V)
Primary Voltage VP (V)
eno (µVRMS/ Hz1/2 )
1000
2.8
2.7
2.6
2.5
1
1
10
2
10
3
10
4
fc (Hz)
10
Figure 9: Output noise voltage spectral density
5
10
6
10
2.4
20 kV/µs
0
0
1
2
3
t (µs)
4
5
6
2.3
7
2.2
8
Figure 10: dv/dt
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LESR series
Typical performance characteristics LESR 25-NP
0.1
4
Rel. Sensitivity 20
Phase
2
10
0
0
0
−0.05
−0.1
−25
−2
−10
−4
−20
−6
−30
−8
−40
−10
1
10
25
IP [A]
Phase [°]
Relative Sensitivity [dB]
Figure 11: Linearity error
2
3
10
4
−50
6
10
5
10
10
Frequency [Hz]
10
Figure 12: Frequency response
30
0.750
25
0.625
20
0.500
15
0.375
Vout−Vref (V)
Linearity Error [ % IP N ]
0.05
IP (A)
IP
Vout−Vref
10
0.250
5
0.125
0
0
100
200
300
t (µs)
400
500
600
Figure 13: Step response
3.5
10000
3.4
600
3.3
3.2
100
10
3.1
400
VP
Vout
Vref
200
3.0
2.9
Vout (V)
Primary Voltage VP (V)
eno (µVRMS/ Hz1/2 )
1000
2.8
2.7
2.6
2.5
1
1
10
2
10
3
10
4
fc (Hz)
10
5
10
Figure 14: Output noise voltage spectral density
6
10
2.4
20 kV/µs
0
0
1
2
3
t (µs)
4
5
6
2.3
7
2.2
8
Figure 15: dv/dt
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LESR series
Typical performance characteristics LESR 50-NP
0.1
4
Rel. Sensitivity 20
Phase
2
10
0
0
0
−0.05
−0.1
−50
−2
−10
−4
−20
−6
−30
−8
−40
−10
1
10
50
IP [A]
Phase [°]
Relative Sensitivity [dB]
Figure 16: Linearity error
2
3
10
4
−50
6
10
5
10
10
Frequency [Hz]
10
Figure 17: Frequency response
30
0.750
25
0.625
20
0.500
15
0.375
IP (A)
IP
Vout−Vref
10
Vout−Vref (V)
Linearity Error [ % IP N ]
0.05
0.250
5
0.125
0
0
100
200
300
t (µs)
400
500
Figure 18: Step response
3.5
10000
3.4
600
3.3
3.2
100
10
3.1
400
3.0
VP
Vout
Vref
200
2.9
Vout (V)
Primary Voltage VP (V)
eno (µVRMS/ Hz1/2 )
1000
2.8
2.7
2.6
2.5
1
1
10
2
10
3
10
4
fc (Hz)
10
Figure 19: Output noise voltage spectral density
5
10
6
10
2.4
20 kV/µs
0
0
1
2
3
t (µs)
4
5
6
2.3
7
2.2
8
Figure 20: dv/dt
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LESR series
Maximum continuous DC primary current
40
100
35
90
30
80
70
60
20
IP (A)
IP (A)
25
15
50
40
30
10
20
5
0
10
0
20
40
60
80
TA (°C)
100
120
0
140
100
40
60
80
TA (°C)
100
120
140
100
120
140
160
90
140
80
120
70
100
IP (A)
60
IP (A)
20
Figure 22: IP vs TA for LESR 15-NP
Figure 21: IP vs TA for LESR 6-NP
50
40
80
60
30
40
20
20
10
0
0
0
20
40
60
80
TA (°C)
100
120
0
140
Figure 23: IP vs TA for LESR 25-NP
0
20
40
60
80
TA (°C)
Figure 24: IP vs TA for LESR 50-NP
The maximum continuous DC primary current plot shows the boundary of the area for which all the following conditions are true:
-- IP < IP M
-- Junction temperature TJ < 125 °C
-- Primary conductor temperature < 110 °C
-- Max power dissipation of internal resistors < 0.5 × resistors nominal power
Frequency derating
Ip AC derating
max AC rms current / max DC rms current
1.33
1
0.66
0.33
0
10
100
1k
fc (Hz)
10k
100k
1M
Figure 25: Maximum RMS AC primary current / maximum DC primary current vs frequency
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LESR series
Performance parameters definition
Ampere-turns and amperes
Magnetic offset
The transducer is sensitive to the primary current linkage ΘP
(also called ampere-turns).
The magnetic offset current IO M is the consequence of a current
on the primary side (“memory effect” of the transducer’s
ferromagnetic parts). It is measured using the following primary
current cycle. IO M depends on the current value IP1 (IP1 > IP M).
ΘP = NP⋅IP (At)
Where NP is the number of primary turn (depending on
the connection of the primary jumpers)
Caution: As most applications will use the transducer with only
one single primary turn (NP = 1), much of this datasheet is
written in terms of primary current instead of current linkages.
However, the ampere-turns (At) unit is used to emphasis that
current linkages are intended and applicable.
Transducer simplified model
The static model of the transducer at temperature TA is:
IS = G⋅ΘP + ε
In which ε =
IO E + IO T (TA) + εG ⋅ΘP⋅G + εL (ΘP max)⋅ΘP max⋅G + TCG⋅(TA−25)⋅ΘP⋅G
With: ΘP = NP⋅IP
ΘP max
IS
TA
IO E
IO T (TA)
G
TCG
εG
εL(ΘP max)
: primary current linkage (At)
: max primary current linkage applied to
the transducer
: secondary current (A)
: ambient operating temperature (°C)
: electrical offset current (A)
: temperature variation of IO at
temperature TA (°C)
: sensitivity of the transducer (V/At)
: temperature coefficient of G
IO M =
Vout(t1) − Vout(t2) 1
·
2
Gth
IP (DC)
IP N
0A
−IP1 t
t2
t1
Ip(3)
Ip(t
3)
Figure 26: C
urrent cycle used to measure magnetic and
electrical offset (transducer supplied)
: sensitivity error
: linearity error for ΘP max
This model is valid for primary ampere-turns ΘP between
−ΘP max and +ΘP max only.
Sensitivity and linearity
To measure sensitivity and linearity, the primary current (DC) is
cycled from 0 to IP, then to −IP and back to 0 (equally spaced
IP/10 steps). The sensitivity G is defined as the slope of the
linear regression line for a cycle between ±IP N.
The linearity error εL is the maximum positive or negative
difference between the measured points and the linear
regression line, expressed in % of IP N.
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LESR series
Performance parameters definition
Electrical offset
Overall accuracy
The electrical offset voltage VO E can either be measured when The overall accuracy at 25 °C XG is the error in the −IP N … +IP N
the ferro-magnetic parts of the transducer are:
range, relative to the rated value IP N.
It includes:
●● Completely demagnetized, which is difficult to realize,
●● the electrical offset VO E
●● or in a known magnetization state, like in the current cycle
shown in figure 26.
●● the sensitivity error εG
Using the current cycle shown in figure 26, the electrical offset
●● the linearity error εL (to IP N)
is:
VO E =
Vout (t1) + Vout (t2)
Response and reaction times
2
VO T (T) = VO E (T) − VO E (25° C)
The response time tr and the reaction time tra are shown in figure
The temperature variation VO T of the electrical offset voltage 28.
VO E is the variation of the
t1) + Vout (t2) offset from 25 °C to the Both depend on the primary current di/dt. They are measured at
Vout (electrical
VO E =
considered temperature:
2
nominal ampere-turns.
VO T (T) = VO E (T) − VO E (25° C)
I
Note: the transducer has to be demagnetized prior to
the application of the current cycle (for example with a
demagnetization tunnel).
100 %
90 %
Vout
Ip
tr
+UC
10 %
Vout
RM
Vref
RL
tra
t
Figure 28: Response time tr and reaction time tra
Figure 27: Test connection
+UC
RM
Vout
Vref
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LESR series
Application information
Filtering and decoupling
Reference Vref
Like the output Vout, the Vref has a very low output impedance of
typically 1 Ohm; it can drive capacitive loads
nF
+U of up to 100
directly. Adding series resistance Rf of several tenths of Ohms
V
R
allows much larger capacitive
loads Cf (higher
than 1 µF).
R
V
Empirical evaluation may be necessary to obtain optimum results.
The minimum load resistance on Vref is 10 kOhms.
Supply voltage UC
C
The transducer has internal decoupling capacitors, but in
the case of a power supply with high impedance, it is highly
recommended to provide local decoupling (100 nF or more,
located close to the transducer) as it may reduce disturbance
on transducer output Vout and reference Vref due to high varying
primary current. The transducer power supply rejection ratio is
low at high frequency.
M
out
ref
L
+UC
Output Vout
RM
The output Vout has a very low output impedance of typically
1 Ohm; it can drive capacitive loads of up to 100 nF directly.
Adding series resistance Rf of several tenths of Ohms allows
much larger capacitive loads Cf (higher than 1 µF). Empirical
evaluation may be necessary to obtain optimum results. The
minimum load resistance on Vout is 1 kOhm.
Vout
Vref
Figure 29: filtered Vout connection
Total Primary Resistance
The primary resistance is 0.72 mΩ per conductor.
In the following table, examples of primary resistance according
to the number of primary turns.
Number Primary
Output
of
Nominal
voltage
primary
RMS
Vout
turns
current
Primary
resistance
RP [mΩ]
±IP N
0.24
Recommended
connections
10
1
2
3
±IP N/2
±IP N/3
Vref ±0.625
Vref ±0.625
1.08
Vref ±0.625
2.16
9
8 OUT
IN 1
2
3
10
9
8 OUT
IN 1
10
2
9
3
8 OUT
IN 1
2
3
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LESR series
External reference voltage
The REF pin can be used either as a reference voltage output or as a reference voltage input.
When used in reference voltage output, the internal reference voltage Vref is used by the transducer as the reference point for
bipolar measurements.
The internal reference voltage output accuracy is defined in the electrical parameter data.
When used in reference voltage input, an external reference voltage is connected to the REF pin.
In this case, the maximun allowable reference voltage range is 0.5 V - 2.75 V.
The REF pin must be able to source or sink an input current of 1.5 mA maximum.
If the reference voltage is not used, the REF pin should be left unconnected.
The following graphs shows the Vref pin current versus forced external Vref.
50
120
40
100
30
80
60
20
40
0
¦
2.75 V
−10
20
0
¦
2.75 V
−20
−40
−20
−60
−30
−80
−40
−50
0.5
IPM (A)
IPM (A)
10
−100
1
1.5
2
Vref (V)
2.5
3
−120
0.5
1
1.5
2
Vref (V)
2.5
3
Figure 30: Measuring range versus external Vref LESR 6-NP
Figure 31: Measuring range versus external Vref LESR 15-NP
Upper limit: IP = −9.6 * Vref + 45.6 (Vref = 0.5 … 2.75 V)
Lower limit: IP = −9.6 * Vref + 2.4 (Vref = 0.5 … 2.75 V)
Upper limit: IP = −24 * Vref + 114
(Vref = 0.5 … 2.75 V)
Lower limit: IP = −24 * Vref + 6
(Vref = 0 … 2.75 V)
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LESR series
External reference voltage
130
200
110
150
90
70
100
50
50
10
¦
−10
2.75 V
IPM (A)
IPM (A)
30
−30
2.75 V
¦
0
−50
−50
−100
−70
−90
−150
−110
−130
0.5
1
1.5
2
Vref (V)
2.5
−200
0.5
3
1
1.5
2
Vref (V)
2.5
3
Figure 32: Measuring range versus external Vref LESR 25-NP
Figure 33: Measuring range versus external Vref LESR 50-NP
Upper limit: IP = −40 *Vref + 190 (Vref = 1.85 … 2.75 V)
Upper limit: IP = 113 (Vref = 0 …1.85 V)
Lower limit: IP = −40 * Vref + 10 (Vref = 0 … 2.75 V)
Upper limit: IP = 150
(Vref = 0 … 2.75 V)
Lower limit: IP = −80 * Vref + 20 (Vref = 0 … 2.125 V)
(Vref = 2.125 … 2.75 V)
Lower limit: IP = −150
Example with Vref = 1.65 V:
●● The 6 A version has a measuring range from −13.44 A to +29.76 A
●● The 15 A version has a measuring range from −33.6 A to +74.4 A
●● The 25 A version has a measuring range from −56 A to +113 A
●● The 50 A version has a measuring range from −112 A to +150 A
Example with Vref = 0.5 V:
●● The 6 A version has a measuring range from −2.4 A to +40.8 A
●● The 15 A version has a measuring range from −6 A to +102 A
●● The 25 A version has a measuring range from −10 A to +113 A
●● The 50 A version has a measuring range from −20 A to +150 A
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LESR series
PCB footprint
Assembly on PCB
●● Recommended PCB hole diameter
1.3 mm for primary pin
0.8 mm for secondary pin
●● Maximum PCB thickness
2.4 mm
●● Wave soldering profile
No clean process only
maximum 260 °C for 10 s
Safety
This transducer must be used in limited-energy secondary circuits according to IEC 61010-1.
This transducer must be used in electric/electronic equipment with respect to applicable standards and safety requirements in
accordance with the manufacturer’s operating instructions.
Caution, risk of electrical shock
When operating the transducer, certain parts of the module can carry hazardous voltage (e.g. primary busbar, power supply).
Ignoring this warning can lead to injury and/or cause serious damage.
This transducer is a build-in device, whose conducting parts must be inaccessible after installation.
A protective housing or additional shield could be used. Main supply must be able to be disconnected.
Remark
Installation of the transducer must be done unless otherwise specified on the datasheet, according to LEM Transducer Generic
Mounting Rules. Please refer to LEM document N°ANE120504 available on our Web site: Products/Product Documentation.
Definition of typical, minimum and maximum values
Minimum and maximum values for specified limiting and safety conditions have to be understood as such as well as values shown
in “typical” graphs.
On the other hand, measured values are part of a statistical distribution that can be specified by an interval with upper and lower
limits and a probability for measured values to lie within this interval.
Unless otherwise stated (e.g. “100 % tested”), the LEM definition for such intervals designated with “min” and “max” is that the
probability for values of samples to lie in this interval is 99.73 %.
For a normal (Gaussian) distribution, this corresponds to an interval between −3 sigma and +3 sigma. If “typical” values are not
obviously mean or average values, those values are defined to delimit intervals with a probability of 68.27 %, corresponding to an
interval between −sigma and +sigma for a normal distribution.
Typical, maximal and minimal values are determined during the initial characterization of the product.
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LESR series
Dimensions (in mm)
Connection
+UC
Vout
Vref
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LESR series
Packaging information
Standard delivery in cardboard: L × W × H: 315 × 200 × 120 mm
Each carboard contains 200 parts, placed into 4 Polystyrene-made trays of 50 parts each one.
Both trays and carboard are ESD-compliant.
The typical weight of the cardboard is 2.5 Kg.
50 transducers per tray
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