LF 310-S

**Current transducer LF 310-S** 

## _I_ **= 300 A PN** 

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

## **Features** 

- ●Bipolar and insulated current measurement up to 500 A 

- ●Current output 

- ●Closed loop (compensated) current transducer 

- ●Panel mounting. 

## **Advantages** 

## **Standards** 

- ●EN 50178: 1997 

- ●IEC 61010-1: 2010 

- ●UL 508: 2010. 

## **Application Domain** 

   - ●Industrial. 

- ●High accuracy 

- ●Very low offset drift over temperature. 

## **Applications** 

- ●Windmill inverters 

- ●Test and measurement 

- ●Substations 

- ●AC variable speed and servo motor drives 

- ●Statics converters for DC motors drives 

- ●Battery supplied applications 

- ●Uninterruptible Power Supplies (UPS) 

- ●Switched Mode Power Supplies (SMPS) 

- ●Power supplies for welding applications. 

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N°97.J9.46.000.0 

LEM reserves the right to carry out modifications on its transducers, in order to improve them, without prior notice 

27October2015/Version 5 

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**LF 310-S** 

## **Absolute maximum ratings** 

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Parameter Symbol Unit Value<br>**----- End of picture text -----**<br>


|**Parameter**|**Symbol**|**Unit**|**Value**|
|---|---|---|---|
|||||
|Maximum supply voltage (working) (−40 … 85 °C)|_±U_C|V|±21|
|Primary conductor temperature|_T_B|°C|100|
|Maximum steady state primary current (−40 … 85 °C)|_I_PN|A|300|



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: 9 

## **Standards** 

- ●USR indicates investigation to the Standard for Industrial Control Equipment UL 508. 

- ●CNR indicates investigation to the Canadian standard for Industrial Control Equipment CSA C22.2 No. 14-13 

## **Conditions of acceptability** 

When installed in the end-use equipment, with primary feedthrough potential involved of 600 V AC/DC, consideration shall be given to the following: 

- _1 - These products must be mounted in a suitable end-use enclosure._ 

- _2 -  The secondary pin terminals have not been evaluated for field wiring._ 

- _3 -  Low voltage control circuit shall be supplied by an isolating source (such as transformer, optical isolator, limiting impedance or electro-mechanical relay)._ 

- _4 -  Based on the temperature test performed on all Series, the primary bar or conductor shall not exceed 100 °C in the end use application._ 

## **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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27October2015/Version 5 

**LF 310-S** 

## **Insulation coordination** 

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Parameter Symbol Unit Value Comment<br>**----- End of picture text -----**<br>


|**Parameter**|**Symbol**|**Unit**|**Value**|**Comment**|
|---|---|---|---|---|
||||||
|Rms voltage for AC insulation test, 50 Hz, 1 min|_U_d|kV|3.8||
|Impulse withstand voltage 1.2/50 µs|_Û_W|kV|10||
|Insulation resistance|_R_IS|MΩ|1000|measured at 3.8 kV AC|
|Comparative tracking index|_CTI_||600||
|Application example|||300 V<br>CAT III, PD2|Reinforced insulation, non<br>uniform feld according to<br>EN 50178, IEC 61010|
|Application example|||1000 V<br>CAT III, PD2|Basic insulation, non<br>uniform feld according to<br>EN 50178, IEC 61010|
|Case material|-|-|V0 according<br>to UL 94||
|Clearance and creepage|See dimensions drawing on page 7||||



## **Environmental and mechanical characteristics** 

|**Parameter**|**Symbol**|**Unit**|**Min**|**Typ**|**Max**|**Comment**|
|---|---|---|---|---|---|---|
|Ambient operating temperature|_T_A|°C|−40||85||
|Ambient storage temperature|_T_S|°C|−50||90||
|Mass|_m_|g||107|||



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27October2015/Version 5 

**LF 310-S** 

## **Electrical data** 

At _T_ A = 25 °C, ± _U_ C = ±15 V, _R_ M = 1 Ω, unless otherwise noted. 

Lines with a * in the conditions column apply over the −40 … 85 °C ambient temperature range. 

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Parameter Symbol Unit Min Typ Max Conditions<br>**----- End of picture text -----**<br>


|**Parameter**|**Symbol**|**Unit**|**Min**|**Typ**|**Max**|**Conditions**|**Conditions**|
|---|---|---|---|---|---|---|---|
|||||||||
|Primary nominal rms current|_I_PN|A|||300|*||
|Primary current, measuring range|_I_PM|A|−500||500|*||
|Measuring resistance|_R_M|Ω|0|||*|Max value of_R_Mis given in fgure 1|
|Secondary nominal rms current|_I_SN|A|−0.15||0.15|*||
|Resistance of secondary winding|_R_S|Ω|||22.5||_R_S(_T_A) =_R_S× (1 + 0.004 × (_T_A+ ∆temp−25))<br>Estimated temperature increase @<br>_I_PNis ∆temp = 15 °C|
|Secondary current|_I_S|A|−0.25||0.25|*||
|Number of secondary turns|_N_S|||2000||||
|Theoretical sensitivity|_G_th|mA/A||0.5||||
|Supply voltage|±_U_C|V|±11.4||±21|*||
|Current consumption|_I_C|mA||33 +_I_S<br>35 +_I_S<br>38 +_I_S|||±_U_C= ±12 V<br>±_U_C= ±15 V<br>±_U_C= ±20 V|
|Offset current, referred to primary|_I_O|A|−0.2||0.2|||
|Temperature variation of_I_O,<br>referred toprimary|_I_O_T_|A|−0.2||0.2|*||
|Magnetic offset current,<br>referred to primary|_I_OM|A||±0.2|||After 3 ×_I_PN|
|Sensitivity error|_εG_|%|−0.1||0.1|*||
|Linearity error|_ε_L|% of_I_PN|−0.05||0.05|*||
|Overall accuracy at_I_PN|_X_G|% of_I_PN|−0.2<br>−0.2||0.2<br>0.2|*|25 … 85 °C<br>−40 … 85 °C|
|Output rms noise current referred<br>to primary|_I_no|mA||35|||1 Hz to 100 kHz (see fgure 4)|
|Reaction time @ 10 % of_I_PN|_t_ra|µs||0.5|||0 to 300 A, 100 A/µs<br>_R_M= 10 Ω|
|Step response time to 90 % of_I_PN|_t_r|µs||0.5|||0 to 300 A, 100 A/µs<br>_R_M= 10 Ω (see fgure 2)|
|Frequency bandwidth|_BW_|kHz||100|||_R_M= 50 Ω; −3 dB|



## **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, minimum and maximum values are determined during the initial characterization of the product. 

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**LF 310-S** 

## **Typical performance characteristics** 

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**----- Start of picture text -----**<br>
U c = 11.4 V @ 85 °C<br>250 UU cc = 14.25 V @ 85 °C = 19 V @ 85 °C<br>200<br>150<br>100<br>300 A, 87    Ω<br>50 300 A, 55    Ω<br>300 A, 36   Ω<br>0<br>50 100 150 200 250 300 350 400 450 500 550<br>I p (A)<br>Figure 1: Maximum measuring resistance<br>R M max =  N S ×   U C min  I − 1.2 V  P −  R S max− 2.4 Ω<br>Noise Voltage Spectral Density<br>−11 0<br>−12 0<br>−13 0<br>−14 0<br>−15 0<br>−16 0<br>−17 0<br>100 101 102 103 104 105 106 107<br>f c (Hz)<br>) Ω<br> (M<br>R<br>1/2)<br>  (dB Vrms/ Hz e n<br>O<br>**----- End of picture text -----**<br>


Figure 1: Maximum measuring resistance 

Figure 3:  Typical noise voltage density eno with _R_ M = 10 Ω 

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Input 100 A /div<br>Output 50 mA/div<br>0 10 20 30 40 50 60 70<br>Time ( µ s)<br>**----- End of picture text -----**<br>


Figure 2: Typical step response (0 to 300 A, 100 A/µs _R_ M = 10 Ω) 

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10−1 Total RMS noise current in the frequency range [1...10] MHz<br>10−2<br>10−3<br>10−4<br>10−5<br>100 101 102 103 104 105 106 107<br>f c (Hz)<br>)rms<br>(A<br>I no<br>Primary referred<br>**----- End of picture text -----**<br>


Figure 4:  Typical total output current noise with (primary referred, rms) with _R_ M _=_ 10 Ω 

To calculate the noise in a frequency band _f_ 1 to _f_ 2, the formula is: 

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with _I_ no ( _f_ ) read from figure 4 (typical, rms value). 

Example: 

What is the noise from 10[3] to 10[6] Hz? 

Figure 4 gives _I_ no (10[3] Hz) = 3.19 mA and _I_ no (10[6] Hz) = 84.4 mA. The output current noise (rms) is therefore: 

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27October2015/Version 5 

**LF 310-S** 

## **Typical performance characteristics** 

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0.1<br>0.05<br>0<br>−0.05<br>−0.1<br>−500 −400 −300 −200 −100 0 100 200 300 400 500<br>Primary Current (A)<br>)Linearity error (% of  I PN<br>**----- End of picture text -----**<br>


Figure 5: Linearity 

## **Performance parameters definition** 

## **Sensitivity and linearity** 

To measure sensitivity and linearity, the primary current (DC) is cycled from 0 to _I_ PM, then to − _I_ PM and back to 0 (equally spaced _I_ PM/10 steps). The sensitivity _G_ is defined as the slope of the linear regression line for a cycle between ± _I_ PM. 

The linearity error _ε_ L is the maximum positive or negative difference between the measured points and the linear regression line, expressed in % of the maximum measured value. 

## **Overall accuracy** 

The overall accuracy _X_ G is the error at ± _I_ PN, relative to the rated value _I_ PN. 

It includes all errors mentioned above. 

## **Response and reaction times** 

The response time next figure. _t_ r and the reaction time _t_ ra are shown in the 

Both slightly depend on the primary current d _i/_ d _t_ . They are measured at nominal current. 

## **Magnetic offset** 

The magnetic offset _I_ OM is the change of offset after a given current has been applied to the input. It is included in the linearity error as long as the transducer remains in its measuring range. 

## **Electrical offset** 

The electrical offset current _I_ OE is the residual output current when the input current is zero. 

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I<br>100 %<br>90 %<br>I P IS<br>t r<br>10 %<br>t ra t<br>**----- End of picture text -----**<br>


Figure 6: Response time _t_ r and reaction time _t_ ra 

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27October2015/Version 5 

**LF 310-S** 

## **Dimensions** (in mm) 

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d CI d Cp<br>10.5 10.8<br>**----- End of picture text -----**<br>


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Connection<br>**----- End of picture text -----**<br>


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I P I S R M 0 V<br>U C<br>U C<br>**----- End of picture text -----**<br>


## **Mechanical characteristics** 

- ●General tolerance 

±0.3 mm 

- ●Transducer fastening 

2 holes ⌀ 4.3 mm 2 M4 steel screws 2.1 N·m (±10 %) 

- Vertical position 

- Recommended fastening torque 

- ●Transducer fastening 

● Horizontal position 4 holes ⌀ 4.3 mm ● 4 M4 steel screws ● Recommended fastening torque 2.1 N·m (±10 %) ●Connection of secondary MOLEX 6410 ⌀ 20 mm 

- ●Primary through hole 

## **Remarks** 

- ●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.** 

## **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. 

- _I_ S is positive when _I_ P flows in the direction of arrow. 

- ●The secondary cables also have to be routed together all the way. 

- ●Installation of the transducer is to be done without primary current or secondary voltage present. 

- ●Maximum temperature of primary conductor: see page 2. 

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

Caution, risk of electrical shock 

When operating the transducer, certain parts of the module can carry hazardous voltage (eg. primary connection, 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. 

LEM reserves the right to carry out modifications on its transducers, in order to improve them, without prior notice 

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