Datasheet

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9November2011/version 14 LEM reserves the right to carry out modications on its transducers, in order to improve them, without prior notice www.lem.com
Current Transducer LA 25-NP
For the electronic measurement of currents: DC, AC, pulsed...,
with galvanic isolation between the primary circuit and the secondary
circuit.
Electrical data
I
PN
Primary nominal current rms 25 At
I
PM
Primary current, measuring range 0 .. ± 36 At
R
M
Measuring resistance @ T
A
= 70°C T
A
= 85°C
R
M min
R
M max
R
M min
R
M max
with ± 15 V @ ± 25 At
max
100 320 100 315 Ω
@ ± 36 At
max
100 190 100 185 Ω
I
SN
Secondary nominal current rms 25 mA
K
N
Conversion ratio 1-2-3-4-5 : 1000
V
C
Supply voltage (± 5 %) ± 15 V
I
C
Current consumption 10 + I
S
mA
Accuracy - Dynamic performance data
X Accuracy @ I
PN
, T
A
= 25°C ± 0.5 %
ε
L
Linearity error < 0.2 %
Typ Max
I
O
Offset current
1)
@ I
P
= 0, T
A
= 25°C ± 0.05 ± 0.15 mA
I
OM
Magnetic offset current
2)
@ I
P
= 0 and specied R
M
,
after an overload of 3 x I
PN
± 0.05 ± 0.15 mA
I
OT
Temperature variation of I
O
0°C .. + 25°C ± 0.06 ± 0.25 mA
+ 25°C .. + 70°C ± 0.10 ± 0.35 mA
- 25°C .. + 85°C ± 0.5 mA
- 40°C .. + 85°C ± 1.2 mA
t
r
Response time
3)
to 90 % of I
PN
step < 1 µs
di/dt di/dt accurately followed > 50 A/µs
BW Frequency bandwidth (- 1 dB) DC .. 150 kHz
General data
T
A
Ambient operating temperature - 40 .. + 85 °C
T
S
Ambient storage temperature - 45 .. + 90 °C
R
P
Primary coil resistance per turn @ T
A
= 25°C < 1.25 mΩ
R
S
Secondary coil resistance @ T
A
= 70°C 110 Ω
  @ T
A
= 85°C 115 Ω
R
IS
Isolation resistance @ 500 V, T
A
= 25°C > 1500 MΩ
m Mass 22 g
Standards EN 50178: 1997
Notes:
1)
Measurement carried out after 15 mn functioning
2)
The result of the coercive eld of the magnetic circuit
3)
With a di/dt of 100 A/µs.
I
PN
= 5-6-8-12-25 At
Features
● Closed loop (compensated)
current transducer using the Hall
effect
● Isolated plastic case recognized
according to UL 94-V0.
Advantages
● Excellent accuracy
● Very good linearity
● Low temperature drift
● Optimized response time
● Wide frequency bandwidth
● No insertion losses
● High immunity to external
interference
● Current overload capability.
Applications
● AC variable speed drives and
servo motor drives
● Static converters for DC motor
drives
● Battery supplied applications
● Uninterruptible Power Supplies
(UPS)
● Switched Mode Power Supplies
(SMPS)
● Power supplies for welding
applications.
Application domain
● Industrial.
16080