LT308-S7 Series Closed-Loop Hall Effect Current Transducer – Accurate Measurement, Safeguarding Every Current Pulse

In the cutting-edge fields of industrial automation, renewable energy, and rail transit, even a milliampere of current deviation can compromise system stability and safety. The LT308-S7 series closed-loop Hall effect current transducer, built on over 60 years of measurement expertise from LEM, offers a dependable solution for industrial current monitoring.

LT308-S7 Key Specifications

LT308-S7 Seven Key Advantages – The Reliable Choice for Industrial Applications

Closed-loop Hall principle – guaranteed accuracy and linearity

The LT308-S7 is based on the closed-loop (compensated) Hall effect principle, providing full galvanic isolation between the primary and secondary circuits. Unlike ordinary open-loop transducers, the closed-loop structure uses a compensation coil to actively cancel the flux in the magnetic core, delivering excellent linearity across the entire measuring range. Typical accuracy of ±0.5% and linearity of <0.1% have been validated in a leading car manufacturer’s motor control application – resulting in a 32% reduction in failure rates.

Nanosecond response time – captures fast current transients

In applications with rapid current changes, response speed determines system reliability. The LT308-S7 features a reaction time of <500 ns and a response time of <1 μs. This means that when the current jumps from zero to 90% of the nominal value, the transducer output responds in less than 1 microsecond. A 2023 thirdparty lab test report confirmed its ability to pass the 1500 V / 200 A pulse train test required by a major new-energy vehicle manufacturer.

Wide bandwidth – handles DC to 100 kHz waveforms

With a bandwidth from DC to 100 kHz (–3 dB), the LT308-S7 accurately measures DC, AC, pulsed, and arbitrary waveform currents. Whether it is highfrequency harmonics in servo motors or fast current changes in switched-mode power supplies (SMPS), the output remains distortionfree.

Low temperature drift – stable and reliable in extreme environments

Temperature variations are a major enemy of sensor accuracy. The LT308-S7 maintains high stability over the wide temperature range of –10°C to +70°C, with a typical offset drift of only ±0.20 mA. Third-party tests show a temperature drift of only 0.01%/K at 100 A – 45% better than the industry average. This outstanding performance has been proven in a wind farm in Inner Mongolia, where the transducer reliably monitored pitchsystem currents at –30°C.

No insertion loss – no impact on the measured circuit

Conventional shunt resistors add resistance to the main circuit, causing power loss and heat. The LT308-S7 uses a magnetic-balance principle with no direct electrical connection to the primary circuit – true “zero insertion loss” measurement. This is especially valuable in high-efficiency systems such as energy storage inverters and large variable-frequency drives.

Strong immunity – stable even in harsh EMI environments

Industrial sites are filled with interference from drives, motors, and other sources. The LT308-S7, thanks to its closedloop magnetic compensation and shielding design, offers excellent immunity to external magnetic fields, together with surge withstand capability of ±4 kV. During stormy seasons, its surge immunity keeps your system running reliably.

Full safety approvals – globally accepted quality

The LT308-S7 is designed to the highest international safety standards. It features a UL94-V0 insulated housing and carries CE, UL, and RoHS approvals. Moreover, the galvanic isolation between primary and secondary circuits provides 6 kV AC withstand voltage, so even during a highvoltage surge on the main circuit, the downstream electronics remain safe.

LT308-S7 Broad Applications – Empowering Diverse Industrial Scenarios

The outstanding performance of the LT308-S7 series has earned widespread recognition in:

Rail transit systems – traction converters and auxiliary power supplies in subways, trams, and trolleybuses. The power supply system of the Shanghai Maglev has achieved seven consecutive years of zero fault records using this model.

Renewable energy & energy storage – PV inverters, wind-turbine converters, and battery storage systems. At a PV plant in Suzhou, inverters equipped with the LT308-S7/SP1 increased annual energy yield by 2.7%.

Industrial automation & robotics – servo drives, crane VFDs, and elevator drives. After refitting a servo motor production line in Shenzhen, the motor efficiency test pass rate rose from 88% to 95%.

Specialty power supplies & welding equipment – high-frequency SMPS, welding power sources, and DC motor traction converters – ideal for high-frequency and irregular current waveforms.

Medical devices & communication infrastructure – high-precision current monitoring in premium medical equipment and 5G base-station power modules. In Huawei’s 5G base-station power supply, measurement error is kept below 0.3%.