LEM LT 308-S7/SP13 Closed-Loop Hall-Effect Current Transducer

Brand: LEM | Model: LT 308-S7/SP13 | Type: Closed-loop Hall-effect current transducer

LT308-S7/SP13 Product Overview

The LEM LT 308-S7/SP13 is a closed-loop (compensated) Hall-effect current transducer featuring galvanic isolation between the primary and secondary circuits. It is designed for precise measurement of DC, AC, and pulsed currents. As part of the classic LT series, this transducer is widely used in variable frequency drives, servo motors, UPS systems, switch-mode power supplies (SMPS), welding power supplies, battery management systems, and industrial automation.

Founded in Geneva, Switzerland in 1972, LEM is a global leader in electrical measurement. In 1973, the company successfully deployed its Hall-effect current transducer on Swiss trams. With over half a century of technological expertise in closedloop and open-loop Hall sensors, LEM has become a key supplier to major automotive OEMs, industrial equipment manufacturers, and energy companies worldwide.

LT308-S7/SP13 Key Specifications & Technical Parameters

With a nominal primary current of ±300 A and a wide measuring range of ±500 A, the LT 308-S7/SP13 delivers typical accuracy of ±0.5% and linearity better than 0.1%. The 100 kHz bandwidth enables accurate capture of signals from power frequency to high-frequency pulsed currents, while the <1 μs response time ensures transient current changes are detected without delay—providing invaluable time for real-time protection and control.

LT308-S7/SP13 Core Advantages & Technical Highlights

Military-grade Closed-Loop Accuracy, Significantly Lower Temperature Drift

The LT 308-S7/SP13 employs LEM’s mature high-performance closed-loop Hall technology, offering substantial improvements in accuracy, linearity, and temperature stability over conventional open-loop solutions. The closed-loop principle uses magnetic compensation to maintain highly stable measurement performance across the operating temperature range—ideal for demanding applications requiring long-term high precision.

Third-party tests show that the sensor has a temperature drift of only 0.01%/K in the 100 A range, which is approximately 45% better than the industry average. Whether in freezing outdoor conditions or hot server rooms, the LT 308-S7/SP13 delivers consistently accurate current data.

High Speed & Strong Noise Immunity – Performs Well in Complex EMI Environments

With a response time <1 μs and di/dt following capability >100 A/μs, the sensor captures nanosecond-scale current transients, providing reliable data for overcurrent protection and fast shutdown. Its excellent immunity to electromagnetic interference ensures stable output even in harsh industrial environments.

Ultra-Long Service Life – 20+ Years of Reliable Operation

The LEM LT 308-S7/SP13 is designed for a service life exceeding 20 years. It uses high-strength materials and an optimized internal structure to withstand electromagnetic interference, temperature fluctuations, and humidity. This significantly reduces long-term maintenance costs. Choosing this sensor means you avoid frequent current-sensing replacements and can offer end products with a reputation for decades of stable operation.

High-Level Galvanic Isolation – All-Round Safety Protection

With 6 mm clearance and 10 mm creepage distance, reinforced by 3.52 kV AC isolation and 6.5 kV impulse withstand voltage, the LT 308-S7/SP13 creates a robust high-voltage barrier between primary and secondary circuits. The UL94-V0 flameretardant housing further ensures equipment and personnel safety in high-voltage environments.

RoHS Compliant – Green Design

The sensor meets RoHS environmental standards with lead-free manufacturing processes, ensuring global regulatory compliance while delivering high performance.

LT308-S7/SP13 Typical Applications

Thanks to its high accuracy, reliability, noise immunity, and wide temperature range, the LT 308-S7/SP13 is the preferred current-sensing solution in many critical industries.

Industrial Automation & Variable Frequency Drives

In motor drive systems, the transducer feeds real-time current signals to the inverter controller to form a closed-loop control. Precise current feedback is essential for high dynamic response and torque accuracy. In one servo motor manufacturer, using the LT308 series improved motor energy-efficiency test pass rates from 88% to 95%, saving over CNY 800,000 annually in rework costs.

UPS & Data Centers

In large-scale data center UPS systems, the sensor continuously monitors charging/discharging currents, helping the battery management system (BMS) accurately calculate state of charge (SOC). Its long life significantly reduces maintenance and replacement frequency, lowering operating costs.

Renewable Energy (PV + Storage + Wind)

In photovoltaic inverters, accurate DC current measurement directly affects MPPT efficiency and annual energy yield. A solar plant in Suzhou reported a 2.7% increase in annual power generation using inverters equipped with LT308-S7/SP1 sensors.

For wind farms, the wide-temperature adaptability of the LT series (-40°C to +85°C) allows reliable current monitoring in pitch control systems even at -30°C in regions like Inner Mongolia.

Electric Vehicles & Charging Infrastructure

In EV motor controllers, the sensor measures bus and phase currents to enable precise torque control and overcurrent protection. In charging stations, a 40% improvement in overcurrent protection response time makes the LT 308-S7/SP13 a reliable choice for enhancing charging safety.

Railway Traction Systems

LEM has over 25 years of experience in the railway industry, where sensors must withstand vibration, shock, wide temperature ranges, and strong electrical noise. In the Shanghai Maglev train power supply system, LT308 series sensors have achieved seven consecutive years of zero failures, a testament to their outstanding long-term reliability.

4.6 Telecom Base Stations & 5G Power Supplies

In Huawei’s 5G base station power modules, the LT308 sensor achieved power consumption monitoring error <0.3%. 5G base stations demand extremely high power efficiency and thermal control. The LT 308-S7/SP13, with its wide bandwidth and