LA305-S/SP5 | High-Precision Closed-Loop Hall-Effect Current Transducer

LA305-S/SP5 Product Overview

The LA305-S/SP5 is a high-precision closed-loop Hall-effect current transducer from LEM (Switzerland) under the LA305 series. Using advanced closed-loop Hall-effect technology, it enables galvanically isolated measurement of DC, AC, and pulsed currents. The nominal current rating is 300 A, with a maximum measuring range of 500 A. The product is RoHS compliant, meeting global environmental production standards, making it an ideal choice for high-accuracy current monitoring and control.

As a world-leading manufacturer of electrical transducers, LEM has a global production network spanning Beijing, Geneva (Switzerland), Tokyo, and Bulgaria, and is renowned for continuous innovation and reliable product quality. From electric locomotives to industrial automation, renewable energy to new energy vehicles, LEM transducers are trusted by engineers worldwide. The LA305-S/SP5 is the embodiment of this technological heritage – a Swiss precision instrument designed for demanding industrial environments.

LA305-S/SP5 Key Highlights & Specifications

Highest Measurement Accuracy

Accuracy: ±0.8%; Linearity: ≤±1%, ensuring stable and true signal reproduction.

Closed-loop Hall technology provides lower temperature drift, better linearity, and higher immunity to interference compared to open-loop solutions – ideal for accuracy-critical applications.

Wide Measuring Range

Nominal current 300 A, maximum measuring range up to 500 A; supports AC+DC bidirectional current measurement.

Whether for rated condition monitoring of motor drives or capturing startup peak currents, the LA305-S/SP5 handles it easily.

Extremely Fast Response

Response time: only 500 ns; wide frequency response from DC to 100 kHz.

Quickly captures transient overcurrent signals, providing reliable overcurrent protection and real-time monitoring – eliminating fault risks in microseconds.

Strong Noise Immunity

Closed-loop Hall technology with output current signal of 120 mA instantaneous.

Provides perfect galvanic isolation between primary and secondary circuits – delivers clean, stable measurement signals even in strong EMI environments such as drives and welding equipment.

Wide Temperature Range & Panel Mount

Operating temperature: -10°C to +85°C, ensuring long-term reliable operation in harsh industrial conditions.

Designed for panel mount – suitable for integration into distribution cabinets and control panels.

25.5 mm × 25.5 mm through-hole for primary conductor – extremely easy installation; output with Faston 6.3×0.8 mm quick-connect terminals – no soldering required.

Model variant comparison: SP1 supports 500 A nominal / 1:2000 turns ratio; SP19 supports -40°C ultra-low temperature; SP6/SP8 are potted versions for enhanced vibration resistance. The SP5 version offers the best price/performance balance within the 300 A range and is widely used in general industry.

LA305-S/SP5 Applications

The LA305-S/SP5 is widely used in industry, railway, energy, automation, and automotive sectors, including:

Motor drives & control – Current monitoring and protection for inverters, servo drives, industrial robots, cranes, elevators, ventilation equipment, etc.

Power supplies – Current monitoring for switching power supplies, server power, telecom rectifiers, UPS systems.

Renewable energy – Current feedback and control in solar inverters and wind power systems.

Railway & traction – Instantaneous current detection, control, and protection in main and auxiliary converters – suitable for harsh railway environments.

Welding equipment – Precision output current detection and feedback for welding machines.

Industrial automation – Signal acquisition for PLCs, secondary instruments, motor protection relays, and power monitoring.

Battery management & automotive electronics – Battery current monitoring in conventional and electric vehicles, as well as onboard chargers.