LV100-1200/SP8 – High-Precision Closed-Loop Hall-Effect Voltage Sensor

LV100-1200/SP8 Product Overview

The LV100-1200/SP8 is a high-performance closed-loop Hall-effect voltage sensor from LEM, part of the LV 100-VOLTAGE series. Designed for accurate voltage measurement in industrial and railway applications, this sensor accurately measures DC, AC, and pulsed voltages while providing galvanic isolation between the primary high-voltage circuit and the secondary electronic circuit, ensuring safe and reliable system operation. As a standard model, the LV100-1200/SP8 is widely used worldwide and is a preferred choice among engineers for voltage monitoring solutions.

LV100-1200/SP8 Core Technology – Closed-Loop Hall Effect

This sensor operates on the closed-loop (compensated) Hall-effect principle. The primary voltage generates a current proportional to the primary voltage through an internal primary resistor, creating a magnetic field in the magnetic core. The compensating magnetic flux produced by the secondary current precisely balances the primary magnetic field, achieving high-accuracy measurement. Compared with open-loop solutions, closed-loop technology offers significant advantages in accuracy, linearity, and temperature stability.

Key advantages of closed-loop Hall-effect voltage sensors include: wide bandwidth from DC up to hundreds of kHz, high accuracy output, excellent linearity, fast dynamic response, low temperature drift, and high safety provided by full galvanic isolation between primary and secondary circuits.

LV100-1200/SP8 Key Performance Specifications

LV100-1200/SP8 Key Advantages

1. High Accuracy – Closed-loop Hall compensation technology delivers overall measurement accuracy of ±0.7% and linearity better than 0.1%. Combined with low temperature drift, it ensures reliable measurement data during long-term operation.

2. TopLevel Safety – Full galvanic isolation between primary and secondary circuits, together with a UL 94-V0 flame-retardant insulated housing, provides a solid safety barrier for personnel and equipment in high-voltage measurement environments. A 6 kV insulation test voltage meets stringent isolation requirements.

3. Excellent Environmental Robustness – Operating temperature range from 0°C to 70°C and a wide storage range from -25°C to 85°C. Low temperature drift and strong immunity to external interference allow the sensor to perform reliably in various complex industrial environments.

4. Wide Frequency Response – The closed-loop Hall technology gives the sensor a superior bandwidth, enabling accurate capture of dynamic changes in DC, AC, and pulsed signals, meeting the signal fidelity requirements of high-performance control systems.

5. Isolated Switching Power Supply – Powered by an external bipolar DC supply (±15 V ±5%), the secondary output is an instantaneous current signal (50 mA). The internal primary resistor is encapsulated, resulting in no insertion loss – simply install and use.

LV100-1200/SP8 Typical Applications

The LV100-1200/SP8 is designed for industrial and traction applications and is widely used in:

AC variable speed drives and servo motor drives – provides accurate voltage feedback for inverters and servo systems, enabling high-performance closedloop control

Static converters for DC motor drives – reliably monitors DC bus voltage for motor control systems

Uninterruptible power supplies (UPS) – ensures output voltage accuracy for critical loads

Welding equipment power supplies – delivers stable voltage monitoring for precision welding processes

Traction systems (including fixed installations and onboard applications):
– Single-phase and threephase inverters
– Propulsion and braking choppers
– Traction converters and auxiliary converters
– Battery chargers

Battery-powered applications – real-time monitoring of battery pack voltage to support efficient battery management systems