LA 125-P/SP3 , LA125-P/SP3

Say Goodbye to Current Measurement Errors – LEM LA125-P/SP3 High-Precision Closed-Loop Hall Effect Current Sensor

Precise, safe, reliable – safeguarding your industrial equipment

LA125-P/SP3 Product Overview

The LA125-P/SP3 is a closed-loop Hall effect current sensor from LEM, a world leader in electrical measurement. It is designed for electronic measurement of DC, AC, and pulsed currents. LEM sensors are widely used in industrial automation, motor drives, energy management, and railway systems.

LA125-P/SP3 Core Technical Features

Closed-Loop Hall Effect Technology – Uncompromising Accuracy

Using closed-loop (compensated) Hall effect technology, the sensor generates a magnetic field from a secondary coil to compensate for the field produced by the primary current. This delivers extremely high accuracy and very low linearity error. Compared with standard open-loop sensors, closed-loop technology offers significant advantages in measurement consistency, temperature stability, and immunity to interference.

Key Specifications:

Key Advantages – Why Choose the LA125-P/SP3?

Outstanding Measurement Accuracy – Confidence in Your Current Data

With accuracy up to ±0.8% and linearity better than 0.15%, every measurement is precise and reliable. Whether for precision motor control or power quality monitoring, you can trust the data.

Ultra-Fast Response – Capture Every Transient

Response time <1 µs and delay <500 ns accurately capture fast current changes, ideal for frequency converters, servo drives, and other real-time closed-loop control applications. With a di/dt tracking capability >200 A/µs, it faithfully reproduces high-dynamic current waveforms.

Electrical Isolation – Safe and Secure

Complete electrical isolation between primary and secondary circuits – insulation test voltage 3 kV (1 minute at 50 Hz), impulse withstand voltage 7 kV (1.2/50 µs pulse). Creepage distance and clearance are both 6.7 mm.

Wide Bandwidth – From DC to 100 kHz

Bandwidth covers DC to 100 kHz (-1 dB). Whether DC component or high-frequency AC signal, the sensor measures accurately. AC/DC bidirectional measurement capability meets the wideband requirements of modern power electronics.

Excellent Environmental Adaptability

Wide operating temperature range: -25℃ ~ +85℃

Optional extended range: -40℃ ~ +85℃ version available

Insulating plastic case meets UL 94-V0 flammability rating

Plug-and-Play Standard Design

Standard PCB through-hole mounting

Primary aperture: 17×4.5 mm or 13×11 mm

Secondary connection: 3-pin 0.63×0.56 mm pins, compatible with LT 100-P series

Two auxiliary mounting holes (Ø1.75 mm) for enhanced PCB assembly stability

Low Power Consumption, No Insertion Loss

Supply current approx. 16 mA (@±15V) – negligible impact on system power. No insertion resistance on the primary side – does not alter the operating condition of the circuit under test. Truly non-intrusive measurement.

LA125-P/SP3 Typical Applications

The LA125-P/SP3 is an ideal current sensing solution for power electronic systems:

AC variable speed drives and servo motor drives – precise current feedback for high-performance motor control

DC motor drive static converters – real-time motor current monitoring for protection and control

Uninterruptible power supplies (UPS) and switch-mode power supplies (SMPS) – monitor input/output current to ensure power stability

Battery powered systems – current monitoring and battery management, extending battery life

Welding power supplies – accurate welding current control for consistent quality

Industrial power supplies, variable frequency drives – reliable current detection for safe equipment operation

Brushless motor drives, stepper drives, servo drives – precise closed-loop current control

Server power supplies, telecom power supplies, general test power supplies – high-accuracy current measurement