LF505-S Closed-Loop Hall Effect Current Transducer — Accurate · Stable · Wide Range

Brand: LEM

Key Advantages: Why Choose LF505-S?

In motor drives, industrial power supplies, renewable energy, and rail transportation, the accuracy and reliability of current measurement directly affect system performance and safety. The LF505-S is a high-performance closed-loop Hall effect current transducer designed to meet these demanding requirements.

The inherent accuracy advantage of closed-loop Hall effect

The LF505-S uses closed-loop (compensated) Hall effect technology. The secondary coil generates a compensating magnetic field that dynamically cancels the field produced by the primary current, keeping the magnetic core at zero flux. Compared to open-loop solutions, the closed-loop structure delivers lower temperature drift, better linearity, and faster response time, maintaining stable output over a wide temperature range – so every measurement you take is trustworthy.

Wide measurement range – ready for transient overcurrents

Beyond the rated 500A RMS measurement capability, the LF505-S offers a measuring range up to ±1200A (@ ±24V supply), easily handling inrush currents, load transients, and other overcurrent events. Whether in normal operation or extreme conditions, this transducer helps protect your system.

LF505-S Key Technical Specifications

LF505-S Key Functional Highlights

Excellent measurement accuracy (±0.6 %) – ensures every current sample is precise and reliable, providing a solid data foundation for system control and protection

Exceptional linearity (< 0.1 %) – maintains linear output from zero to full scale, delivering consistent, trustworthy measurements without complex calibration

Outstanding immunity to external interference – suitable for frequency converters, motor drives and other high-EMI environments; measurement stability remains unaffected

Low temperature drift design – offset current variation ≤ ±0.8 mA across the wide -40℃ to +70℃ operating range, meeting the demands of outdoor and extreme applications

Microsecond response time (< 1 µs delay) – quickly captures transient current changes, providing ample margin for overcurrent protection and real-time control

Wide frequency response (DC to 100 kHz) – covers DC, power frequency, harmonics and high-frequency pulse components, fully reproducing the current waveform

Current overload capability – momentary overloads do not damage the transducer, adding an extra layer of system safety

No insertion loss – does not alter the power characteristics of the measured circuit, saving energy and reducing waste

Compact design, flexible mounting – only 230g, 30.2 mm aperture, supports multiple panel mounting options for easy integration into various equipment

LF505-S Application Fields

With its outstanding electrical performance and proven reliability, the LEM LF505-S is widely used in:

Motor drives & frequency converters – current monitoring and closed-loop control in singlephase/three-phase inverters and servo drives

Industrial power supplies – input/output current detection in switch-mode power supplies and UPS systems

Renewable energy – current monitoring in photovoltaic inverters and wind power converters

Rail transportation – propulsion and braking choppers, auxiliary converters, onboard battery chargers, and other railway rolling stock equipment

Welding equipment – precise control and monitoring of welding current

Traction systems – control and protection for main traction and auxiliary frequency converters