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Closed loop (compensated) current transducer using the Hall effect
| Primary Current, Measuring Range | 0 ... ±350 A |
| Secondary Nominal Current | 125 mA |
| Supply Voltage | ±15 V |
| Operating Temperature Range | −40 ... +85 °C |
| Isolation Test Voltage | 3.6 kV |
| Primary Nominal RMS Current (IPN) | 250 A |
Single or three phases inverters, Propulsion and braking chopper, Propulsion converter, Auxiliary converter, Battery charger.
The LF 305-S/SP7 is a closed loop (compensated) current transducer from LEM for the electronic measurement of currents: DC, AC, pulsed..., with galvanic isolation.
It offers excellent accuracy, very good linearity, low temperature drift and wide frequency bandwidth. Typical applications include Single or three phases inverters, Propulsion and braking chopper, Propulsion converter and Auxiliary converter.
Key characteristics from the official datasheet: total error ±0.5 %; linearity error < 0.1 %; frequency bandwidth DC ... 100 kHz; operating temperature −40 ... +85 °C; nominal secondary output 125 mA.
| General Information | |
|---|---|
| Manufacturer | LEM |
| Product Series | LF |
| Product Reference | LF 305-S/SP7 |
| Primary Nominal Current | 250 A |
| Supply Voltage | ±15 V |
| Measurement | currents: DC, AC, pulsed... |
| Mounting | Busbar Mount |
| Application Domain | Railway |
| Electrical Data — LF 305-S/SP7 | |
|---|---|
| Primary Nominal RMS Current (IPN) | 250 A |
| Primary Current, Measuring Range (IPM) | 0 ... ±350 A |
| Secondary Nominal RMS Current (ISN) | 125 mA |
| Turns Ratio (NP/NS) | 1 : 2000 |
| Supply Voltage (UC) | ±15 V |
| Current Consumption (IC) | 16 +I mA |
| Accuracy & Dynamic Performance | |
|---|---|
| Total Error (εtot) @ IPN | ±0.5 % |
| Linearity Error (εL) | < 0.1 % |
| Frequency Bandwidth (BW) | DC ... 100 kHz |
| Insulation Coordination | |
|---|---|
| RMS Voltage for AC Insulation Test (50 Hz, 1 min) Ud | 3.6 kV |
| Impulse Withstand Voltage (1.2/50 µs) UNi | 9 kV |
| Creepage Distance (dCp) | 10.1 mm |
| Clearance (dCI) | 10.1 mm |
| Comparative Tracking Index (CTI) | 175 |
| Environmental & Mechanical Characteristics | |
|---|---|
| Ambient Operating Temperature (TA) | −40 ... +85 °C |
| Ambient Storage Temperature (TA st) | −45 ... +90 °C |
| Mass (m) | 100 g |
| Case Material | Insulating plastic case recognized according to UL 94-V0. |
| General Tolerance | ±0.5 mm |
| Standards & Certifications | |
|---|---|
| EN 50155 | 2017 |
Note: Specifications are taken from the official LF 305-S/SP7 datasheet. Parameters that could not be confirmed from the datasheet are marked UNVERIFIED.
Official technical documentation for the LF 305-S/SP7.
Outline dimensions, pin layout and connection diagrams of the LF 305-S/SP7 are shown below.
| Outline Dimensions & Mechanical Data | |
|---|---|
| General Tolerance | ±0.5 mm |
| Mass | 100 g |
| Case Material | Insulating plastic case recognized according to UL 94-V0. |
Note: All dimensions are in millimetres. Refer to the official datasheet for the complete dimension drawing.
Typical applications of the LF 305-S/SP7.
Characteristic curve diagrams are not included in the LF 305-S/SP7 datasheet; the relevant characteristics are the accuracy and dynamic performance data listed below.
| Accuracy & Dynamic Characteristics | |
|---|---|
| Total Error (εtot) @ IPN | ±0.5 % |
| Linearity Error (εL) | < 0.1 % |
| Frequency Bandwidth (BW) | DC ... 100 kHz |
Note: For the full set of performance data, refer to the datasheet.
Other models of the LF Series share the same measurement principle, mounting concept and output interface family.
