HAS300-S | LEM Original High-Precision Open-Loop Hall-Effect Current Sensor

Industrial non-contact current measurement solution – 300A rated, ±1% accuracy, DC~50kHz bandwidth. Provides safe, isolated current measurement for your power systems.

HAS300-S Product Overview

The HAS300-S is a high-precision open-loop Hall-effect current sensor from LEM, a world leader in electrical measurement. Designed for electronic measurement of DC, AC, and pulse currents, this sensor features electrical isolation between the primary and secondary circuits. It is widely used in variable frequency drives, uninterruptible power supplies (UPS), switch-mode power supplies (SMPS), and welding power supplies.

In complex industrial environments requiring accurate current monitoring, the HAS300-S has become a trusted choice for engineers thanks to its excellent stability and noise immunity.

HAS300-S Key Specifications

HAS300-S Key Advantages

Compact Design – Saves Up to 50% Installation Space

With maximum dimensions of only 50×50×50mm, the HAS300-S occupies nearly 50% less space than conventional current sensing solutions. This compact design allows easy integration into space-constrained devices such as smart meters and distribution panels, reducing retrofit costs and providing unprecedented flexibility.

Wide Range + High Accuracy – Reliable Energy Metering

The ±900A wide measurement range combined with ±1% accuracy ensures stable and precise output from low-current daily monitoring to high-current peak detection. The Hall-effect measurement principle delivers excellent temperature stability and long-term reliability, even in complex electromagnetic environments.

3µs Fast Response – Captures Transient Changes

With a response time of just 3µs and a frequency bandwidth of DC~50kHz, the sensor quickly captures instantaneous current changes, meeting the demanding transient response and fault detection requirements of UPS systems, inverters, and similar applications.

Electrical Isolation & Insulation Protection – Double Safety

The HAS300-S provides electrical isolation between the primary and secondary circuits with an insulation resistance >1000MΩ @ 500V DC. The housing is made of UL 94-V0 rated insulating plastic, ensuring reliable protection for operators and downstream equipment.

Low Power Consumption + Easy Installation – Reduced Operating Costs

With a current consumption of only ±15mA, the HAS300-S offers very low power draw, helping to reduce overall system energy consumption. The modular design allows for quick and easy installation without major equipment modifications.

HAS300-S Product Comparison

The HAS300-S uses an open-loop Hall-effect architecture. Compared to closed-loop or fluxgate solutions, this design offers a simpler structure, lower cost, and wider adaptability while maintaining sufficient measurement accuracy. It is particularly well-suited for industrial applications that require large-scale deployment with considerations for cost and ease of installation.

HAS300-S Main Applications

The HAS300-S is widely used in the following industrial power electronics fields:

Variable Frequency Drives – AC variable speed drives, static DC motor drive converters

Power Protection – UPS (uninterruptible power supplies), switch-mode power supplies (SMPS)

Industrial Power – Welding power supplies, battery-powered equipment

Smart Grid – Smart meters, power distribution monitoring systems

Renewable Energy – PV inverters, EV charging stations

Why choose the HAS300-S?

As demands for measurement accuracy and system reliability grow, the HAS300-S delivers industrial-grade precision, fast response, and an excellent balance of compactness, low power consumption, and ease of use. Whether for new system designs or retrofitting existing equipment, the HAS300-S is a trustworthy core component for your current sensing solutions.