The story of LEM began in 1972 in Geneva, Switzerland. Two brothers, Jean-Pierre and Marcel Etter, engineers and researchers in the then-new field of power electronics, embarked on the adventure with some friends. Very quickly, they started to develop the first current transducer and won their first contract to equip the tramways of the city of Geneva.
This success was the first of many. The quality and reliability of LEM's current and voltage sensing solutions quickly became an absolute reference.
Today, LEM's expertise in electrical measurement simply shows when looking at the portfolio. LEM offers the widest range of current measurement solutions to customers’ needs around the world in automation, drives and welding, renewable energies, UPS, traction and trackside, high precision, automotive, conventional and electrical vehicles, smart grids, etc.
From Current Sensors to Integrated Current Sensors
LEM has always viewed current sensing and measurement as a function, not as a technology or a “final product”. That's why LEM engineers have never stopped developing new alternatives for measuring electrical parameters.
Traditionally, LEM has established itself as the world leader in measuring high currents in large applications. However, LEM has continued to build on this expertise in current sensing, and its engineering and R&D teams have further explored new territory in current sensing. The objective has always been to serve customers' needs and to evolve with them.
For more than 15 years now, the pure player in electrical measurement has been developing know-how and expertise in the tiniest environments by developing excellence in designing ASICs (Application Specific Integrated Circuits) compatible with the smallest electrical circuits.
This evolution is in line with LEM's philosophy of offering high-quality solutions while accompanying their customers' mutations. The world of electronics is changing rapidly, and one of the major trends is to combine smaller, smarter, cheaper. LEM's ICS range is a response to this trend.
A unique know-how for all systems where electricity is flowing
LEM has been consistently offering alternatives to passive current measurement with clever solutions using different technologies: Hall effect, fluxgate, Rogowski, etc. in different environments.
In high voltage applications, LEM's Integrated Current Sensors can provide sensors with local isolation as opposed to the shunt technology which requires a distinct electrical signal acquisition and processing circuit.
For lower currents, shunts remain an alternative; however, they still present isolation problems and need to be combined with several additional electronic components to complete the current sensing function.
Being in a continuous search for robust, reliable, and optimized solutions for its customers' applications, LEM has strived to bring its knowledge and expertise to the latest electrical systems and to reliably provide the current measurement function with ever smaller, smarter, cheaper solutions.
That's how Integrated Current Sensors (ICS) were born at LEM. They result from 50 years of fundamental electrical knowledge, a deep understanding of customer applications, and a continuous investment in product innovation. ICS have established themselves as the most optimized hardware for high-accuracy current sensing in all environments.
Outstanding advances in semiconductor manufacturing and packaging now enable all the stages of a current sensor to be integrated into a single package. How is this possible? The current runs through the device, while the induced magnetic field is detected by two Hall-effect plates. There is no contact and the device is inherently galvanically isolated. An application-specific integrated circuit (ASIC) processes the voltage signal and enables additional ad hoc functions to be added.
LEM is now building a complete ICS range to serve evolving needs as well as new applications emerging with the electrification of our world.
Within the existing range of integrated current sensors, LEM offers the GO series and the HMSR SMS series as well as the brand new HMSR DA, the first ICS with digital bitstream output. And there is more on the roadmap.
LEM at a glance
Since 1972, LEM has been playing a major role worldwide in providing cutting-edge current sensing solutions.
Since then, LEM further develops its expertise and know-how in the area of ASIC design, software development, project management, manufacturing, and current measurement system calibration.
LEM has state-of-the-art production sites in Beijing (China), Geneva (Switzerland), Sofia (Bulgaria), and Tokyo (Japan), and will shortly be opening a new facility in Malaysia.
Through its regional offices based close to its customer sites, LEM ensures optimum servicing all over the world. Since 1986, LEM has been quoted on the SIX Swiss Exchange. Its stock market symbol is LEHN.