LF 205-S/SP1 , LF205-S/SP1

LEM LF 205-S/SP1 Closed-Loop Hall Effect Current Sensor

LF 205-S/SP1 Product Overview

The LF 205-S/SP1 is a high-precision current sensor based on closed-loop Hall effect technology, from LEM (Switzerland), the global leader in electrical measurement. Featuring closed-loop compensation technology, it is designed for electronic measurement of DC, AC, and pulsed currents, with galvanic isolation between the primary and secondary circuits.

The sensor operates on a ±12V to ±15V bipolar supply, with a rated current of 200A, a measuring range of up to ±420A (2.1x overload capability), and a 100mA current output. It features a Molex Mini-Fit Jr 5566 standard connector for reliable and convenient wiring. With a 15.5mm aperture, an operating temperature range of -40°C to +85°C, it complies with EN 50178, EN 50155, and EN 50121-3-2 international standards.

LF 205-S/SP1 Key Technical Specifications

LF 205-S/SP1 Key Advantages

Closed-Loop Hall Technology: Active compensation design eliminates core saturation effects — accuracy ±0.5%, linearity <0.1%

<1µs Fast Response: Reaction time <500ns — perfectly matched for high-frequency IGBT/PWM switching applications

DC~100kHz High Bandwidth: Accurately measures DC and AC current up to 100kHz — suitable for modern high-frequency power supplies

Superior Noise Immunity: Closed-loop architecture provides high external magnetic field rejection — stable operation in complex industrial EMI environments such as VFDs and high-power drives

2.1x Overload Capability: Measuring range up to ±420A — handles motor starting and load transient current surges

-40℃~+85℃ Wide Temperature Range + Low Drift: EN 50155 railway standard compliant — temperature drift only ±0.4mA — suitable for outdoor enclosures, rail transit, and other extreme temperature scenarios

15.5mm Aperture + Flexible Mounting: Easy busbar or conductor passage — supports both horizontal and vertical panel mounting options — fits various industrial cabinet layouts

Why Choose the LF 205-S/SP1?

±0.5% High Accuracy + <0.1% Linearity: Closed-loop compensation technology ensures accurate measurement across the full range — meets industrial precision control requirements

<1µs Fast Response: Accurately captures IGBT switching transients and current spikes during load changes — provides timely and reliable triggering signals for overcurrent protection

100kHz High Bandwidth: Accurately measures current waveforms up to 100kHz — perfectly matches the output characteristics of modern high-frequency switching power supplies and VFDs

3.5kV High-Voltage Isolation + 8.8kV Impulse Withstand: Reinforced insulation between primary and secondary — ensures control system safety, compliant with EN 50178 industrial safety standards

-40℃~+85℃ Wide Temperature Operation + EN 50155 Certified: Certified to railway rolling stock equipment standards — suitable for locomotive traction, outdoor enclosures, and other extreme temperature scenarios

Molex Mini-Fit Jr 5566 Connector: Standardized interface — convenient and reliable wiring — reduces on-site installation costs

LF 205-S/SP1 Target Applications

AC variable frequency drives and servo motor drives, DC motor drive static converters, UPS systems, switch-mode power supplies (SMPS), welding power supplies, traction systems (propulsion and braking choppers, traction converters, auxiliary converters), battery-powered equipment, renewable energy systems, single-phase/three-phase inverters