LF505-S/SP34；LF 505-S/SP34

‌LF505-S/SP34 Product Description: The Modern Standard in Industrial Current Sensing

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LF505-S/SP34 ‌Product Overview‌
The LF505-S/SP34 is a high-performance closed-loop Hall effect current sensor from LEM, engineered for precise measurement of DC, AC, and pulsed currents in demanding industrial environments. Utilizing magnetic flux compensation technology, it provides galvanic isolation between the primary high-current circuit and the secondary control electronics, delivering a linear proportional current output without direct electrical contact. As the current production model in the LF505-S series, the SP34 represents the latest evolution of proven closed-loop sensing technology, offering seamless replacement for legacy and discontinued variants while maintaining full compatibility with existing system designs.

LF505-S/SP34 ‌Key Features‌

‌Closed-loop Compensation Accuracy‌: Achieves ±0.6% overall accuracy and <0.1% linearity through magnetic balance control, eliminating zero-point drift and temperature-induced errors—ensuring long-term stability without recalibration.

‌Microsecond Dynamic Response‌: ≤1 µs response time enables precise capture of transient current events and high-frequency pulses, meeting the real-time feedback demands of servo drives and fast-switching power converters.

‌Wide Bandwidth Coverage‌: Supports DC to 100 kHz measurement bandwidth, compatible with diverse current waveforms from DC bus lines to high-frequency inverters in modern power electronics.

‌Bidirectional Current Sensing‌: Simultaneously measures positive and negative current flow without external polarity switching circuits, enabling critical data for energy recovery, battery charge/discharge control, and motor regenerative braking.

‌Industrial Environmental Robustness‌: Encased in UL94V-0 flame-retardant engineering plastic, rated for operation from -40°C to +70°C, ensuring reliable performance under harsh vibration, thermal cycling, and industrial noise conditions.

‌Zero Insertion Loss Design‌: Closed-loop architecture prevents core saturation, delivering near-zero series impedance to minimize power loss and thermal impact on the measured circuit.

LF505-S/SP34 ‌Technical Specifications‌

‌Rated Current‌: 500 A RMS

‌Measurement Range‌: 0 to ±800 A

‌Supply Voltage‌: ±15 V to ±24 V

‌Output Type‌: Proportional current output (100 mA full scale)

‌Response Time‌: ≤1 µs

‌Operating Temperature‌: -40°C to +70°C

‌Insulation Voltage‌: 3500 V RMS, compliant with EN 50178 safety isolation standards

‌Mounting Type‌: Chassis mount, single-hole through-core design (φ36 mm), compatible with M6 mounting screws for easy integration into distribution cabinets or control modules

‌Certifications‌: Complies with EN 50155 (railway applications), EN 50178 (industrial electrical equipment), and RoHS

LF505-S/SP34 ‌Applications‌
The LF505-S/SP34 serves as a core sensing element in modern industrial power systems, deployed in:

Industrial variable frequency drives and servo systems for precise torque and speed closed-loop control

Modular switch-mode power supplies (SMPS) and uninterruptible power supplies (UPS) to ensure output waveform stability and overcurrent protection accuracy

Electric vehicle DC fast charging stations for real-time monitoring of high-current charging processes, enhancing efficiency and safety

Railway traction converters to enable energy recovery, braking control, and fault diagnostics

Photovoltaic and energy storage inverters for precise grid-current control and maximum power point tracking (MPPT) feedback

‌Why Choose LF505-S/SP34 This Model‌
The LF505-S/SP34 is not merely an upgrade—it is the current production standard that carries forward the legacy of its predecessors while ensuring supply chain continuity and technical support. It matches the electrical performance of the discontinued SP35 but benefits from ongoing manufacturing quality control and global technical documentation. Compared to open-loop sensors, its closed-loop architecture delivers superior long-term stability and noise immunity. Compared to newer models, its proven interface, pin compatibility, and established control algorithms eliminate the need for system redesign. Choosing the LF505-S/SP34 means selecting a sensor validated across tens of thousands of industrial installations—where precision, durability, and reliability are non-negotiable. No compromise. No obsolescence risk. Just proven performance.