LT505-S/SP3 Closed-Loop Hall Effect Current Transducer

LT505-S/SP3 The Industry Benchmark for Accuracy and Reliability

In demanding applications such as industrial automation, railway traction, and renewable energy generation, even tiny current measurement errors can cause protection system misoperation or energy loss. The LT505-S/SP3 closed-loop Hall effect current transducer is a professional-grade measurement solution specifically designed for these high-requirement industrial scenarios.

Key Advantages – Why Choose the LT505-S/SP3?

Closed-loop compensation technology for superior accuracy
Unlike conventional open-loop Hall sensors that directly measure magnetic field strength, the LT505-S/SP3 uses a closed-loop (compensated) architecture. An internal compensation winding generates a reverse magnetic flux that precisely cancels the flux produced by the primary current, keeping the magnetic core at zero flux. This design achieves outstanding measurement accuracy – ±0.6% over the full range. The rated primary current is 500 A, with a maximum measuring range up to 1000 A, sufficient for the vast majority of industrial current monitoring needs.

Wide temperature stability – reliable in extreme environments
The LT505-S/SP3 operates over a temperature range of -40°C to 85°C. Whether in freezing outdoor conditions or hot industrial workshops, it maintains stable measurement performance. The internal low-drift ferrite core and dual temperature compensation resistor network keep zero-point drift extremely low – the measured zero drift over the -40°C to 85°C range is only about 0.18 mA, effectively avoiding system misjudgment caused by temperature drift.

Wide ±15 V to ±24 V supply voltage – compatible with various control systems
The transducer supports a bipolar supply from ±15 V to ±24 V, offering flexibility for different electrical platform designs and simplifying system integration.

150 kHz wideband response – captures transient changes
With a frequency bandwidth of 150 kHz, ±0.1 % linearity, and a response time of approximately 1 μs, the LT505-S/SP3 accurately captures DC, AC, pulsed, and irregular waveforms. It is especially suitable for dynamic applications such as variable frequency drives and switch-mode power supplies.

Galvanic isolation between primary and secondary – safe and reliable
The transducer provides electrical isolation between the primary (high-voltage) and secondary (electronic) circuits. The insulation voltage is 3500 V (at 25°C / 1 min / 50 Hz). It measures high-side currents safely without insertion loss, ensuring the safety of both the control system and operators.

Overload protection – built-in self-protection
When the primary current exceeds the rated value, the transducer enters overload protection mode and outputs a status signal. This prevents damage to the transducer while also alerting the system to an overload condition.

LT505-S/SP3 Wide Range of Applications

The LT505-S/SP3 is suitable for industrial applications according to EN 50178. With its high accuracy, high stability, and wide temperature range, it plays a key role in many fields:

AC variable speed drives and servo drives – precise motor current control, improving energy efficiency

Static converters for DC motor drives – stable speed regulation

Uninterruptible power supplies (UPS) – realtime current monitoring for critical loads

Switchmode power supplies (SMPS) – accurate current feedback for optimized power design

Renewable energy generation (photovoltaic inverters, wind turbine generators, etc.) – efficient grid connection

Batterypowered applications – accurate current monitoring for energy storage systems

Welding equipment power supplies – stable output for reliable weld quality

As a globally recognised brand in electrical measurement, LEM’s transducers are widely used in industry, railway, energy automation, and new energy vehicles, with high quality and proven reliability.

LT505-S/SP3Technical Specifications at a Glance