LEM LA 55-P Datasheet

Current Transducer LA 55-P

For the electronic measurement of currents: DC, AC, pulsed...,
with galvanic separation between the primary circuit and the secondary
circuit.

Electrical data

IPN = 50 A

IPN Primary nominal rms current 50 A
I

Primary current, measuring range 0 .. ±70 A

PM

R

Measuring resistance @ TA = 70 °C TA = 85 °C

M

R

with ±12 V @ ±50 A
@ ±70 A
with ±15 V @ ±50 A
@ ±70 A

I

Secondary nominal rms current 50 mA

SN

K

Conversion ratio 1 : 1000

N

U

Supply voltage (±5 %) ±12 .. 15 V

C

I

Current consumption 10 (@ ±15 V) + IS mA

C

10 100 60 95 Ω

max

10 50 60 1) 60 1) Ω

max

50 160 135 155 Ω

max

50 90 135 2) 135 2) Ω

max

M min

R

M max RM min

R

M max

Accuracy - Dynamic performance data

X Accuracy @ IPN, TA = 25 °C @ ±15 V (±5 %) ±0.65 %
@ ±12 .. 15 V (±5 %) ±0.90 %

ε

Linearity error <0.15 %

L

Typ Max

I

Offset current @ IP = 0, TA = 25 °C ±0.2 mA

O

I

Magnetic offset current 3) @ IP = 0 and specied RM,

OM

after an overload of 3 × I
I

Temperature variation of IO -25 °C .. +85 °C ±0.1 ±0.6 mA

OT

±0.3 mA

PN

-40 °C .. -25 °C ±0.2 ±1.0 mA
t

Reaction time <500 ns

ra

t

Step response time to 90 % of IPN <1 µs

r

di/dt di/dt accurately followed >200 A/µs

BW Frequency bandwidth (-1 dB) DC .. 200 kHz

General data

TA Ambient operating temperature -40 .. +85 °C
T

Ambient storage temperature -40 .. +90 °C

S

R

Resistance of secondary winding @ TA = 70 °C 80 Ω

S

  @ T
m Mass 18 g
Standards EN 50178: 1997
UL 508: 2010

= 85 °C 85 Ω

A

Features

● Closed loop (compensated)
current transducer using the Hall

effect

● Insulating 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.

1)

Notes:

N° 97.13.25.000.0

15June2015/version 16 LEM reserves the right to carry out modications on its transducers, in order to improve them, without prior notice www.lem.com

Measuring range limited to ±60 A

2)

Measuring range limited to ±55 A

3)

Result of the coercive eld of the magnetic circuit.

max

max

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Current Transducer LA 55-P

Cp

W

Reinforced insulation

150 V

150 V

Insulation coordination

Ud Rms voltage for AC insulation test, 50 Hz/1 min 2.5 kV
Û

Impulse withstand voltage 1.2/50 µs 5.7 kV

W

Min
d

Creepage distance 5 mm

Cp

d

Clearance 5 mm

CI

CTI Comparative tracking index (group I) 600

Applications examples

According to EN 50178 and IEC 61010-1 standards and following conditions:

● Over voltage category OV 3

● Pollution degree PD2

● Non-uniform eld

EN 50178 IEC 61010-1

, dCI, Û

d

Basic insulation 300 V 300 V

Rated insulation voltage Nominal voltage

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 (eg. 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.

15June2015/version 16 LEM reserves the right to carry out modications on its transducers, in order to improve them, without prior notice www.lem.com

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Dimensions LA 55-P (in mm)

I

d

Cl

d

Cp

U

C

I

S

I

P

R

M

d

Cl

d

Cp

I

S

I

P

R

M

d

Cl

d

Cp

Connection

P

I

R

S

M

U

C

U

C

Mechanical characteristics

● General tolerance ±0.2 mm

● Primary through-hole 12.7 × 7 mm

● Fastening & connection of secondary 3 pins

0.6 × 0.7 mm

● Recommended PCB hole ⌀ 1.2 mm

d

Cl

d

Cp

Remarks

● IS is positive when IP ows in the direction of the arrow.

● Temperature of the primary conductor should not exceed

90 °C.

● Installation of the transducer must be done unless

otherwise specied 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.

● Dynamic performances (di/dt and response time) are best

with a single bar completely lling the primary hole.

● In order to achieve the best magnetic coupling, the
primary windings have to be wound over the top edge of
the device.

● This is a standard model. For different versions (supply
voltages, turns ratios, unidirectional measurements...),
please contact us.

15June2015/version 16 LEM reserves the right to carry out modications on its transducers, in order to improve them, without prior notice www.lem.com

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