LEM LV100/SP81 High-Precision Closed-Loop Hall-Effect Voltage Transducer

LV100/SP81 Product Overview

The LV100/SP81 is a professional voltage transducer using closed-loop Hall-effect technology, designed and manufactured by LEM, a global leader in sensor technology. Its essential galvanic isolation design provides electrical separation between the primary high-voltage circuit and the secondary electronic circuit, effectively ensuring the safety of downstream electronics and operators. The device performs precise electronic measurement of DC, AC, and pulsed voltages, and is especially suited for a wide range of industrial applications with nominal voltages from 100V to 2500V.

As a representative model of the LV100 series, the SP81 version stands out with its instantaneous unidirectional 50 mA secondary output signal and 0.7% high accuracy. It excels in voltage monitoring applications in metallurgy, chemical, railway traction, power supplies, and electric vehicle systems.

LV100/SP81 Key Features & Benefits

Advanced Closed-Loop Hall-Effect Technology

The LV100/SP81 uses advanced closedloop (compensated) Halleffect technology. Compared to conventional openloop sensors, it offers lower temperature drift, higher linearity, and stronger antiinterference capability, maintaining stable measurement performance even in complex electromagnetic environments.

Wide Voltage Measurement Range

Through an external resistor R1, the device can be flexibly configured to cover a broad voltage range of 100V to 2500V, meeting diverse requirements from lowvoltage distribution to medium and highvoltage power systems.

Stable Operation Over Wide Temperature Range

With an operating temperature range of -40°C to +85°C, the LV100/SP81 delivers consistently accurate measurement signals whether in extreme cold, heat, or humidity fluctuations typical of industrial environments.

Excellent Galvanic Isolation

The galvanic isolation between primary and secondary circuits not only ensures safety for downstream electronics but also significantly reduces commonmode interference and ground loops, providing a clean measurement signal for precision control systems.

Panel Mounting for Flexible Integration

Standard panel mounting design facilitates easy integration into control cabinets, distribution panels, and professional test equipment, saving installation space and improving system integration efficiency.

LV100/SP81 Technical Specifications

LV100/SP81 Typical Applications

Thanks to its outstanding accuracy, isolation performance, and wide operating temperature range, the LV100/SP81 is widely used in the following fields:

Industrial drives and servo control – Provides precise feedback for DCbus voltage monitoring in variable frequency drives, enabling accurate motor control.

Renewable energy and photovoltaic inverters – Monitors DC and AC side voltages in solar inverters and energy storage systems, ensuring conversion efficiency and system safety.

Railway traction – Used for voltage monitoring in train traction systems, meeting demanding requirements for high reliability and vibration resistance.

Active power filters (APF) – Responds quickly to voltage variations in harmonic mitigation equipment, ensuring clean and stable power grids.

Laboratory testing and precision measurement – Provides reliable voltage monitoring for highprecision test instruments.

Specialty power supplies and welding equipment – Operates reliably under harsh conditions with high voltage and high current.

Why Choose the LEM LV100/SP81?

Swissoriginated precision quality – LEM is a global market leader and benchmark in sensor technology, with operations in more than 15 countries. Its core products are widely used in drives, welding, renewable energy, power supplies, and electric vehicles.

Mature and reliable closedloop technology – Compared to openloop alternatives, the LV100/SP81 offers superior temperature stability, lower offset drift, and higher measurement bandwidth, handling challenging dynamic voltage variations.

Flexible system integration – Users can easily select and add an external resistor R1 to adapt the device to voltage levels from 100V to 2500V, allowing flexible range configuration.

Long service life and high costeffectiveness – The model is active and has a stable supply chain. Its outstanding reliability has been proven in longterm industrial field applications.