LA55-P/SP1 Closed-Loop Hall-Effect Current Transducer – Accurate · Compact · Reliable, Protecting Your Power Electronics System

LA55-P/SP1 Product Overview

The LEM LA55-P/SP1 is a high-performance closed-loop Hall-effect current transducer designed for industrial applications, enabling precise electronic measurement of DC, AC, and pulsed currents. With extremely low error, outstanding linearity, a compact footprint, and excellent electrical isolation, this transducer has become the go-to choice for engineers working on variable frequency drives, servo motor controls, renewable energy equipment, and industrial power supplies.

LA55-P/SP1 Key Selling Points

High Accuracy – ±0.65% Error

The LA55-P/SP1 employs advanced closed-loop (compensated) Hall-effect technology, achieving an error of just ±0.65% at rated current and a linearity error below 0.15%. With a wide operating temperature range from -40℃ to +85℃ – whether in a hot production workshop or a cold outdoor environment – it delivers consistently accurate current data, ensuring your control system receives the most reliable feedback.

Extremely Fast Response – Nanosecond Protection

In overcurrent protection and fault detection, response speed is critical to system safety. The LA55-P/SP1 delivers a response time of less than 500 ns and a rise time to 90% of final output of just 1 μs. This means the system receives accurate data and can take protective action almost instantly when an abnormal current occurs, minimising the risk of equipment damage. For IGBT modules requiring high-frequency switching, this transducer fully meets real-time protection needs.

Small Size, Big Performance – Easy Integration

Measuring only 36.5 mm × 27.6 mm × 14.45 mm and weighing just 18 g, the transducer is designed for PCB mounting. Its compact form factor allows easy integration into space-constrained circuit boards and systems, with no need for complex auxiliary circuits – plug and play, significantly reducing development time and design effort.

Strong Electrical Isolation – Safe and Reliable

The LA55-P/SP1 provides complete galvanic isolation between the primary (high-voltage power) side and the secondary (electronic circuit) side, with an isolation test voltage of 2.5 kVrms (power frequency AC test voltage). The UL 94-V0 certified insulating plastic housing further enhances safety, making your design reliable even under high-voltage conditions.

Why Choose the LA55-P/SP1?

Excellent anti-interference capability – The closed-loop Hall-effect principle gives the transducer outstanding immunity to external interference, maintaining stable operation even in strong electromagnetic environments such as variable frequency drives.

No insertion loss – The transducer has virtually no effect on the measured circuit and does not reduce system efficiency.

Low temperature drift – The temperature-induced offset current is extremely low: only ±0.05 mA over the -25℃ to +85℃ range, ensuring measurement consistency over the full temperature range.

High overload capability – Even after momentary overloads, the magnetic offset current is very small, allowing measurement accuracy to recover quickly.

Wide frequency bandwidth – DC to 200 kHz covers the frequency requirements of most industrial control applications.

Bidirectional current measurement – Supports a measuring range of ±100 A, meeting the need for both forward and reverse current measurement.

LA55-P/SP1 Typical Applications

Industrial Drive Control

In AC variable frequency drives and servo motor drives, the LA55-P/SP1 accurately monitors motor current, helping optimise control algorithms, improve motor efficiency, and detect overload or short-circuit faults to protect equipment. One automotive parts manufacturer reported that after switching to this transducer, system accuracy improved to 0.5% and annual power loss decreased by 7.8%.

Renewable Energy

In photovoltaic inverters, the LA55-P/SP1 can monitor both DC and AC side currents in real time, optimising the MPPT (Maximum Power Point Tracking) algorithm and helping solar panels operate at peak efficiency. Industry data shows that inverters using this transducer can achieve a 2–3% increase in total power generation.

Power Management Systems

Suitable for UPS, switch-mode power supplies (SMPS), battery-powered systems, and welding equipment power supplies. A well-known charging pile manufacturer reported that after adopting the LA55-P/SP1, current measurement accuracy improved by approximately 30% and the failure rate fell by about 25%.

Rail Transit and Smart Manufacturing

A rail transit equipment supplier revealed that after using the LA55-P/SP1 in train traction systems, fault diagnosis accuracy increased to 99.6%. In the field of industrial robots, even with highfrequency interference up to 200 kHz, the transducer remains stable, helping to achieve positioning accuracy down to 0.02 mm.