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Closed loop (compensated) current transducer using the Hall effect
| Primary Current, Measuring Range | 0 ... ±36 At |
| Secondary Nominal Current | 25 mA |
| Supply Voltage | ±15 V |
| Operating Temperature Range | −40 ... +85 °C |
| Isolation Test Voltage | 4 kV |
| Primary Nominal RMS Current (IPN) | 25 At |
Single or three phase inverters, Propulsion and braking choppers, Propulsion converters, Auxiliary converters, Battery chargers. Application Domain, Railway (fixed installations and onboard).
The LA 25-NP/SP25 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 phase inverters, Propulsion and braking choppers, Propulsion converters and Auxiliary converters.
Key characteristics from the official datasheet: total error ±0.9 %; linearity error < 0.2 %; frequency bandwidth DC ... 150 kHz; operating temperature −40 ... +85 °C; nominal secondary output 25 mA.
| General Information | |
|---|---|
| Manufacturer | LEM |
| Product Series | LA |
| Product Reference | LA 25-NP/SP25 |
| Primary Nominal Current | 25 At |
| Supply Voltage | ±15 V |
| Measurement | currents: DC, AC, pulsed... |
| Mounting | PCB Mount |
| Application Domain | Railway (fixed installations and onboard) |
| Electrical Data — LA 25-NP/SP25 | |
|---|---|
| Primary Nominal RMS Current (IPN) | 25 At |
| Primary Current, Measuring Range (IPM) | 0 ... ±36 At |
| Secondary Nominal RMS Current (ISN) | 25 mA |
| Turns Ratio (NP/NS) | 1-2-3-4-5 : 1000 |
| Supply Voltage (UC) | ±15 V |
| Current Consumption (IC) | 10 + I mA A |
| Accuracy & Dynamic Performance | |
|---|---|
| Total Error (εtot) @ IPN | ±0.9 % |
| Linearity Error (εL) | < 0.2 % |
| Frequency Bandwidth (BW) | DC ... 150 kHz |
| Insulation Coordination | |
|---|---|
| RMS Voltage for AC Insulation Test (50 Hz, 1 min) Ud | 4 kV |
| Impulse Withstand Voltage (1.2/50 µs) UNi | 9 kV |
| Creepage Distance (dCp) | 10.63 mm |
| Clearance (dCI) | 10.63 mm |
| Comparative Tracking Index (CTI) | 175 |
| Environmental & Mechanical Characteristics | |
|---|---|
| Ambient Operating Temperature (TA) | −40 ... +85 °C |
| Ambient Storage Temperature (TA st) | −50 ... +100 °C |
| Mass (m) | 22 g |
| Case Material | Insulating plastic case recognized according to UL 94-V0. |
| Primary Connection | 10 pins 0.7 × 0.6 mm |
| Recommended PCB Hole | 1.2 mm |
| General Tolerance | ±0.2 mm |
| Standards & Certifications | |
|---|---|
| EN 50155 | 2017 |
| UL 508 | Compliance |
Note: Specifications are taken from the official LA 25-NP/SP25 datasheet. Parameters that could not be confirmed from the datasheet are marked UNVERIFIED.
Official technical documentation for the LA 25-NP/SP25.
Outline dimensions, pin layout and connection diagrams of the LA 25-NP/SP25 are shown below. The primary turns configuration table lists the available primary ratings.
| Outline Dimensions & Mechanical Data | |
|---|---|
| Primary Connection | 10 pins 0.7 × 0.6 mm |
| Recommended PCB Hole | 1.2 mm |
| General Tolerance | ±0.2 mm |
| Mass | 22 g |
| Case Material | Insulating plastic case recognized according to UL 94-V0. |
| Primary Turns | IPN Nominal [A] | IP Max [A] | ISN Output [mA] | Turns Ratio | RP [mΩ] | LP [µH] |
|---|---|---|---|---|---|---|
| 1 | 25 | 36 | 25 | 1 / 1000 | 0.3 | 0.023 |
| 2 | 12 | 18 | 24 | 2 / 1000 | 1.1 | 0.09 |
| 3 | 8 | 12 | 24 | 3 / 1000 | 2.5 | 0.21 |
| 4 | 6 | 9 | 24 | 4 / 1000 | 4.4 | 0.37 |
| 5 | 5 | 7 | 25 | 5 / 1000 | 6.3 | 0.58 |
Note: All dimensions are in millimetres. Refer to the official datasheet for the complete dimension drawing.
Typical applications of the LA 25-NP/SP25.
Characteristic curve diagrams are not included in the LA 25-NP/SP25 datasheet; the relevant characteristics are the accuracy and dynamic performance data listed below.
| Accuracy & Dynamic Characteristics | |
|---|---|
| Total Error (εtot) @ IPN | ±0.9 % |
| Linearity Error (εL) | < 0.2 % |
| Frequency Bandwidth (BW) | DC ... 150 kHz |
Note: For the full set of performance data, refer to the datasheet.
Other models of the LA 25-200 Series share the same measurement principle, mounting concept and output interface family.
