Current Transducer LF 305-S
For the electronic measurement of currents : DC, AC, pulsed...,
with a galvanic isolation between the primary circuit (high power)
and the secondary circuit (electronic circuit).
Electrical data
I
PN
Primary nominal r.m.s. current
300
A
I
P
Primary current, measuring range
0 .. 500
A
R
M
Measuring resistance
R
M min
R
M max
with 12 V
@ 300 A
max
0
39
@ 500 A
max
0
12
with 15 V
@ 300 A
max
0
58
@ 500 A
max
0
22
with 20 V
@ 300 A
max
15
93
@ 500 A
max
15
45
I
SN
Secondary nominal r.m.s. current
150
mA
K
N
Conversion ratio
1 : 2000
V
C
Supply voltage ( 5 %)
12 .. 20
V
I
C
Current consumption
16
(@ 20 V)
+
I
S
mA
V
d
R.m.s. voltage for AC isolation test, 50 Hz, 1 mn
3
kV
Accuracy - Dynamic performance data
X
G
Overall accuracy @
I
PN
,
T
A
= 25C
0.4
%
L
Linearity
< 0.1
%
Typ
Max
I
O
Offset current @
I
P
= 0,
T
A
= 25C
0.20 mA
I
OM
Residual current
1)
@
I
P
= 0, after an overload of 3 x
I
PN
0.08 mA
I
OT
Thermal drift of
I
O
- 10C .. + 70C
0.1 0.30 mA
t
ra
Reaction time @ 10 % of
I
PN
< 500
n s
t
r
Response time
2)
@ 90 % of
I
PN
< 1
s
di/dt
di/dt
accurately followed
> 100
A/s
f
Frequency bandwidth (- 1 dB)
DC .. 100
kHz
General data
T
A
Ambient operating temperature
- 10 .. + 70
C
T
S
Ambient storage temperature
- 25 .. + 85
C
R
S
Secondary coil resistance @
T
A
= 70C
28
m
Mass
95
g
Standards
3)
EN 50178
Notes :
1)
The result of the coercive field of the magnetic circuit
2)
With a di/dt of 100 A/s
3)
A list of corresponding tests is available
Features
Closed loop (compensated) current
transducer using the Hall effect
Insulated 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.
I
PN
= 300
A
991125/1
LEM Components
w w w .lem.com
Preliminary
Remarks
I
S
is positive when
I
P
flows in the direction of the arrow.
Temperature of the primary conductor should not exceed
100C.
Dynamic performances (di/dt and response time) are best
with a single bar completely filling the primary hole.
This is a standard model. For different versions (supply
voltages, turns ratios, unidirectional measurements...),
please contact us.
Mechanical characteristics
General tolerance
0.5 mm
Fastening
see drawing
Primary through-hole
20 mm
Connection of secondary
Molex 5045-03/AG
Dimensions LF 305-S
(in mm. 1 mm = 0.0394 inch)
Right view
Back view
Top view
Secondary terminals
Pin + : supply voltage + 12 .. 20 V
Pin M : measure
Pin - : supply voltage - 12 .. 20 V
Bottom view
Connection
LEM reserves the right to carry out modifications on its transducers, in order to improve them, without previous notice.
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