LF 305-S

## **Current Transducer LF 305-S** 

## _I_ **= 300 A** PN 

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

## ~~**Electrical data** Lo~~ 

|_I_PN|Primary nominal rms current||300|300||A|
|---|---|---|---|---|---|---|
|_I_PM|Primary current, measuring range||0 .. ± 500|||A|
|_R_M|Measuring resistance @<br>|_T_A= 70 °C|||_T_A= 85 °C||
|||_R_M min _R_M max|||_R_M min _R_M max||
||with ± 12 V<br>@ ± 300 Amax|0|37||0<br>35|Ω|
||@ ± 500 Amax<br>with ± 15 V<br>@ ± 300 Amax|0<br>0|10<br>56||0<br>8<br>0<br>54|Ω<br>Ω|
||@ ± 500 Amax|0|21||0<br>19|Ω|
||with ± 20 V<br>@ ± 300 Amax|0|88||0<br>86|Ω|
||@ ± 500 Amax|0|40||0<br>38|Ω|
|_I_SN|Secondary nominal rms current||150|||mA|
|_K_N|Conversion ratio||1 : 2000|1 : 2000|||
|_U_C|Supply voltage (± 5 %)||± 12 .. 20||± 12 .. 20|V|
|_I_C|Current consumption||26 (@ ±|26 (@ ±20 V) +_I_SmA||mA|



|~~**Accuracy - Dynamic performance data**~~<br>~~ee~~<br>~~1/4 N A~~|~~**Accuracy - Dynamic performance data**~~<br>~~ee~~<br>~~1/4 N A~~|~~**Accuracy - Dynamic performance data**~~<br>~~ee~~<br>~~1/4 N A~~|~~**Accuracy - Dynamic performance data**~~<br>~~ee~~<br>~~1/4 N A~~|~~**Accuracy - Dynamic performance data**~~<br>~~ee~~<br>~~1/4 N A~~|~~**Accuracy - Dynamic performance data**~~<br>~~ee~~<br>~~1/4 N A~~|
|---|---|---|---|---|---|
|_X_G|Overall accuracy @_I_PN,_T_A= 25 °C|||± 0.5|%|
|_ε_L|Linearity error|||< 0.1|%|
|||||Typ<br>Max||
|_I_O<br>_I_OM|Offset current @_I_P= 0,_T_A= 25 °C<br>Magnetic offset current1)@_I_P= 0 and specified_R_M|||± 0.2|mA|
||after an overload of 3 x_I_PN|||± 0.2|mA|
|_I_O_T_|Temperature variation of_I_O<br>- 10 °C .. + 70 °C<br>- 40 °C .. + 85 °C||||± 0.1 ± 0.3<br>± 0.2 ± 0.7|mA<br>mA|
|_t_ra|Reaction time to 10 % of_I_PN|||< 500|ns|
|_t_r|Step response time2)to 90 % of_I_PN|||< 1|µs|
|d_i_/d_t_|d_i_/d_t_accurately followed|||> 100|A/µs|
|_BW_|Frequency bandwidth (- 1 dB)|||DC .. 100|kHz|
|~~**General data**~~<br>~~Pr~~<br>~~(i~~||||~~ee~~|~~ee~~|
|_T_A<br>_T_S|Ambient operating temperature<br>Ambient storage temperature|||- 40 .. + 85<br>- 40 .. + 85|°C<br>°C|
|_R_S|Resistance of secondary winding @_T_A= 70 °C|||30|Ω|
||@ _T_A= 85 °C|||32|Ω|
|_m_|Mass|||95|g|
||Standards|||EN 50178: 1997||
|||||UL 508: 2010||



## **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. 

Notes:[1)] The result of the coercive field of the magnetic circuit 

- 2) With a d _i_ /d _t_ of 100 A/µs. 

N° 97.14.46.000.0 

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

8May2014/version 12 

www.lem.com 

## **Current Transducer LF 305-S** 

|~~**Insulation coordination**~~|~~**Insulation coordination**~~|||
|---|---|---|---|
|_U_d|Rms voltage for AC insulation test, 50 Hz, 1 min|3.8|kV|
|_Û_W|Impulse withstand voltage 1.2/50 µs|10|kV|
|||Min||
|_d_Cp|Creepage distance|11.1|mm|
|_d_CI|Clearance|10.6|mm|
|_CTI_|Comparative tracking index (group IIIa)|175||



## **Applications examples** 

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

- ●Over voltage category OV 3 

- ●Pollution degree PD2 

- ●Non-uniform field 

||**EN 50178**|**IEC 61010-1**|
|---|---|---|
|_d_Cp,_d_CI,_Û_W|Rated insulation voltage|Nominal voltage|
|Basic insulation|1000 V|1000 V|
|Reinforced insulation|500 V|500 V|



## **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. 

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

8May2014/version 12 

www.lem.com 

## **Dimensions LF 305-S** (in mm) 

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## **Mechanical characteristics** 

- ●General tolerance 

± 0.5 mm 

●Transducer fastening Vertical position 2 holes Ø 4.3 mm 2 M4 steel screws Recommended fastening torque 3.2 N·m or 4 holes Ø 1.9 mm, depth: 7 mm 4 PTKA 25 screws length: 6 mm Recommended fastening torque 0.7 N·m 

●Transducer fastening Horizontal position 4 holes Ø 4.3 mm 4 M4 steel screws Recommended fastening torque 3.2 N·m or 4 holes Ø 1.9 mm crossing 4 PTKA 25 screws, length: 10 mm Recommended fastening torque 0.75 N·m ●Primary through-hole Ø 20.1 mm ●Connection of secondary Molex 6410 3 Tin plated pins 

## **Remarks** 

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

- ●Temperature of the primary conductor should not exceed 100 °C. 

- ●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** . 

- ●Dynamic performances (d _i_ /d _t_ and response time) are best with a single bar completely filling the primary hole. 

8May2014/version 12 LEM reserves the right to carry out modifications on its transducers, in order to improve them, without prior notice 

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www.lem.com