LEM
United States

LEM USA Inc.

11665 West Bradley Road
Milwaukee, WI, 53224
United States

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INNOVATIONS

Since 1972, LEM has been responding to their customer’s demands by investing in continuous research and development. This investment has allowed LEM to not only create new products but also improve existing product performance, cost efficiency and size by introducing new features and functions that create a competitive advantage with added value, in final applications. LEM believes that a close relationship with the customer is the key to discover and develop the products of the future. LEM’s extensive product portfolio uses 7 key technologies to fulfil the needs of the market. These technologies create a wide range of galvanically isolated current and voltage transducers that have become industry standards within the measurement field.
To support the various electrical and mechanical requirements from the market, LEM have developed a range of technologies, these include:
  • Hall effect Open loop technology
  • Hall effect Closed loop technology
  • Fluxgate technologies, including “IT-types“, “C-types“, “CTSR types“, “CAS-CASR-CKSR type” and “ITC type”
  • Insulating digital technology, including “DVL & DVM & DV type”  
  • Air-core technologies including Rogowski coil, PRiME™ and Current Transformers types
While most applications will find that the best solution for their need is a standard transducer from one of the technology ranges above, LEM is fully capable of developing customized solutions to meet the customer’s specific requirements.

Technologies

Closed Loop Current Transducers
Closed Loop Current Transducers
Closed Loop Fluxgate C type
Closed Loop Fluxgate C type
Closed Loop Fluxgate CAS-CASR-CKSR Type
Closed Loop Fluxgate CAS-CASR-CKSR Type
Closed Loop Fluxgate CTSR type
Closed loop flux gate CTSR type
Closed Loop Fluxgate IT type
Closed Loop Fluxgate IT type
Closed Loop Fluxgate ITC type
Closed Loop Fluxgate ITC type
Closed Loop Voltage Transducers
Closed Loop Voltage Transducers
DV & DVL & DVM Type Voltage Transducers
DV & DVL & DVM Type Voltage Transducers
Open-Loop Current Transducers
Open-Loop Current Transducers
PRiME Current Transducers
PRiME Current Transducers
Rogowski Current Transducers
Rogowski Current Transducers
Split Core Current transformers AT & TT Type
Split Core Current transformers AT & TT Type

Current Transducers

LEM is a leading supplier of current transducers (also called current sensors), offering a wide range of galvanically isolated transducers that have become industry standards. The broad range of sizes, measuring range from tiny currents to 24kA and ease of use make them ideal solutions for a broad range of applications.

LEM offers a variety of current sensor technologies:

  • Hall Effect
  • Fluxgate 
  • Air-Core (Coreless)
     

Hall Effect Current Transducers

LEM Hall Effect current sensors are available in open-loop, closed-loop and Eta configurations. Open-loop Hall Effect sensors are highly cost effective, as well as being small and consuming minimal power. Closed-loop sensors offer higher accuracy and enhanced speed to enable currents with a wider range of frequencies to be measured.     

Hall Effect Eta transducers are similar in construction to closed loop transducers , with the same magnetic circuit geometry, a Hall generator and secondary winding. A Hall Effect Eta transducer is a mix of open loop and current transformer technologies operating as an open loop transducer at low frequencies (up to 2…10 kHz depending on the specific transducer design), and as a current transformer at higher frequencies. Both the Hall Effect and transformer signals are electronically added to form a common output signal.

Hall Effect Current Transducers
 

Fluxgate Current Transducers

A “standard” closed-loop Fluxgate sensor uses a secondary winding to counteract the field generated in a magnetic circuit by the primary conductor. Although similar in operation to a closed-loop Hall Effect sensor, the Fluxgate uses a saturable inductor using a small thin magnetic core to sense the airgap field, rather than a Hall Effect transducer.

Fluxgate Current Transducers

Other Fluxgate transducers built on the technology to deliver specific benefits. They are:

  • Low-Frequency, where the field sensing element is wrapped around the toroidal core, rather than using a gap to make more cost-effective sensors
  • C-Type, built like the low-frequency Fluxgate sensor, but with a separate core to improve high frequency performance
  • IT-type that uses two toroidal cores with opposing excitation coils.
     

Air-Core Current Transducers

The material used to create the core can limit the performance of the transducer due to characteristics such as remanence, hysteresis, non-linearity, losses and saturation. So the design of an air-core or coreless transducer is often considered.

Examples of air-core current sensors include Rogowski coil transducers.

More information:

For more information about different current transducer technologies, download Isolated Current and Voltage Transducers: Characteristics, Applications, Calculations.
To find a current transducer for your application, visit the LEM Current Transducer Selector Tool.
 

Voltage Transducers

LEM offers a wide range of voltage transducers (also called voltage sensors) to allow isolated measurement of voltage. The broad range of products measures voltage from 10 V to 6.4 kV, with a variety of technologies including Hall Effect,Fluxgate and insulating digital.

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