LT4000-S/SP43 High-Current Closed-Loop Hall Effect Current Sensor

LT4000-S/SP43 Product Overview

The LT4000-S/SP43 is a high-performance, high-current closed-loop Hall effect current sensor from LEM (Switzerland), part of the LT4000 series. Designed for industrial power electronics systems, it operates on a ±24V bipolar supply and provides non-contact isolated measurement of rated currents up to 4000 A, with a maximum measurable range of 6500 A. It combines ultra-high accuracy with excellent response speed, making it a leading choice for large current measurement applications.

As a product of LEM – a global leader in electrical measurement (founded in 1972, listed on the Swiss Stock Exchange, ticker: LEHN) – the LT4000-S/SP43 leverages advanced closed-loop Hall effect technology. With an accuracy of 0.5%, outstanding linearity, and extremely low temperature drift, it is widely used in AC variable frequency drives, servo motor controls, industrial power supplies, photovoltaic inverters, welding equipment, and uninterruptible power supplies (UPS).

Whether you need to protect multi-million dollar metallurgical equipment or improve the energy efficiency of railway traction systems, the LT4000-S/SP43 is a trustworthy guardian. LEM products are certified under ISO 9001, ISO 14000, TS 16949, and comply with RoHS requirements, ensuring high brand credibility and safety assurance.

LT4000-S/SP43 Key Technical Advantages

Closed-Loop Hall Effect Technology
The LT4000-S/SP43 uses closed-loop (compensated) Hall effect technology, which effectively cancels magnetic flux in the core, delivering higher accuracy, faster response, and a wider frequency range than open-loop sensors. It provides galvanic isolation between the primary (high-power) circuit and the secondary (electronic) circuit, protecting downstream control systems.

±0.5% High Accuracy
At 25°C ambient temperature, the overall accuracy reaches ±0.5% with linearity better than 0.1%, ensuring reliable and repeatable measurements in complex industrial environments – ideal for precision motor control and energy metering.

Wide Measurement Range
The sensor supports rated RMS current up to 4000 A, with a maximum measuring range up to 6500 A (peak). The primary aperture diameter is 102 mm, easily accommodating large busbars or thick cables for convenient installation.

Superior Frequency Characteristics
Bandwidth up to 100 kHz (-1dB) combined with a di/dt tracking capability exceeding 50 A/μs allows accurate capture of fast transient currents, such as PWM waveforms from inverters or short-circuit currents.

Wide Temperature Stability
Operating temperature range from -40°C to 85°C ensures stable performance even in harsh environments – suitable for outdoor solar power stations, highaltitude railway traction substations, or desert oil drilling platforms.

Fast Response
Response time <1 μs (at 100 A/μs di/dt), ideal for short-circuit protection and overcurrent fast shutdown where real-time performance is critical, enhancing system safety.

LT4000-S/SP43 Technical Specifications

LT4000-S/SP43 Typical Applications

LEM sensors are widely used in industrial automation, rail, energy, and automotive sectors. With its 4000 A high-current capability and robust mechanical design, the LT4000-S/SP43 excels in:

Industrial drives & servo motor control – Large VFDs, AC/DC motor drives, servo systems for closed-loop current control, improving efficiency and smoothness.

Renewable energy generation – Photovoltaic inverters, wind turbine converters for DC or AC side current monitoring, supporting grid connection and power optimization.

Metallurgy, chemical & electrolysis industries – High DC current monitoring in non-ferrous smelting, chlor-alkali electrolysis, enabling real-time process tuning and energy savings.

Large industrial power supplies & welding equipment – SMPS, welding machines, induction heating power supplies for precise power control and short-circuit protection.

Railway traction systems – Traction converters for locomotive main current control and auxiliary power protection.

UPS & battery energy storage – Monitoring UPS inverter output and battery charge/discharge currents for overload protection and energy management.

Why Choose LT4000-S/SP43?

Among many high-current sensors, the LT4000-S/SP43 stands out with four core strengths:

Swiss precision, industry reputation
LEM is one of the inventors of Hall effect current sensors and a de-facto standard setter since 1972. Many global equipment manufacturers – especially in traction, industrial power, and renewables – specify LEM sensors as standard. The LT4000-S/SP43 has been proven stable in hundreds of thousands of installations worldwide.

High current capability, easy aperture installation
The 102 mm large aperture allows direct insertion of busbars or thick cables without disassembling existing wiring – simplifying retrofits and avoiding connectionrelated safety risks.

High accuracy & strong noise immunity
Closedloop Hall technology provides excellent rejection of external stray magnetic fields, delivering stable and accurate signals even in high-EMI environments (inverters, large power converters), eliminating costly magnetic shielding.

Wide-temperature, allweather operation
The -40°C to 85°C operating range has passed rigorous accelerated aging and environmental tests, suitable for frigid northern wind farms as well as hot industrial workshops.