LA125-P Closed-Loop Hall-Effect Current Sensor

Rated current: 125A | Measuring range: ±200A | Accuracy: ±0.8% | Response time: <1μs

LA125-P Product Overview

The LA125-P is a closed-loop Hall-effect current sensor from LEM, the world leader in electrical measurement. Designed for precise measurement of DC, AC, and pulsed currents up to 125A RMS, it uses closed-loop (compensation) technology to provide galvanic isolation between the primary (high power) and secondary (electronic) circuits, ensuring system safety and signal integrity. It is an ideal choice for industrial power supplies, motor drives, UPS, and new energy applications.

LA125-P Key Advantages

The LA125-P integrates multiple technical benefits to help your system achieve higher performance and reliability.

Excellent Accuracy and Linearity : With an accuracy of ±0.8% at room temperature and linearity error below 0.15%, it delivers reliable current signals even under complex operating conditions, providing precise data support for your control system.

Ultra-Fast Dynamic Response : A response time of less than 1 microsecond allows it to faithfully follow current slew rates exceeding 100A/µs. It captures transient events such as inverter switching spikes and overload surges, giving valuable time window for overcurrent protection.

Stable Operation Over a Wide Temperature Range : Operates reliably from -40℃ to +85℃. Optimized internal temperature compensation ensures low thermal drift, keeping measurements consistent across the full temperature range.

High Noise Immunity and Overload Capability : Excellent immunity to external electromagnetic interference and a strong overload withstand capability. A high isolation voltage rating of 8.4 kVrms ensures safe system operation.

PCB Through-Hole Mounting : Standard through-hole package for direct soldering onto PCBs. Compact design, easy integration, and reduced development time.

LA125-P Technical Specifications

LA125-P Typical Applications

With its outstanding performance, the LA125-P is widely used in:

AC variable speed drives and servo motor drives – Accurate current feedback is essential for motor control; the LA125-P provides high-precision current monitoring for better speed and torque control.

Static converters for DC motor drives – Precisely measures motor current, offering reliable current detection for DC drive systems.

Uninterruptible Power Supplies (UPS) and Switch Mode Power Supplies (SMPS) – Real-time monitoring of input/output current ensures stable, efficient operation and provides protection under fault conditions.

Battery powered applications – Accurately measures battery charge/discharge currents, optimises battery management and extends battery life.

Welding power supplies – Withstands high pulsed currents, provides stable output feedback, improving welding quality.

Industrial automation equipment – Suitable for current monitoring in industrial robots, cranes, lifts, ventilation and air conditioning equipment, servers, telecom base station power supplies, and many other scenarios.

Why Choose the LEM LA125-P?

As the market leader in electrical sensors, LEM has over 50 years of technical expertise and industry experience, trusted worldwide in industrial, railway, energy, automotive, and automation sectors. Choosing the LA125-P means you get more than just a component – you receive a mature, proven technical solution backed by a 5year warranty, a global technical support network, and a broad product portfolio (from 0.25A to 10kA, covering open-loop, closed-loop, Eta, and other technologies) to meet all your current measurement needs in different projects. Choose the LA125-P – choose a reliable current measurement solution.