Current Transducers Measure Up to 450Apk with Closed-loop Hall Effect TechnologyMay 08, 2019 by Paul Shepard
LEM announced the LZSR family of transducers, a new range that can be mounted on printed circuit boards (PCBs) for non-intrusive, isolated measurements of dc, ac and pulsed currents from 100A to 200A nominal. Announced during PCIM Europe 2019, the family consists of three new models: LZSR 100-P, LZSR 150-P and LZSR 200-P.
These new transducers are based on LEM’s latest leading-edge ASIC technology, which has been proven with the launches of the LF xx10, LH, LxSR current transducer series. Used in a closed loop mode, the ASIC based on Hall effect technology, can reach a low offset drift up to 3 ppm/K of VREF.
This new family takes advantage of these benefits at currents such as 100, 150 and 200A nominal. Working over a temperature range from -40°C to +85°C, LZSR offset drift is much better than the previous generation of Closed-loop Hall effect current transducers working with traditional Hall effect chip (up to 7-times better).
Operating from a single supply voltage of +5V, the LZSR models measure peak current up to 3-times the primary nominal current reaching 450Apk with the 150ARMS nominal model (LZSR 150-P/SP1). They provide their internal reference voltage to a VREF pin.
An overcurrent detection output with a threshold set at 1.93 x IPN is also offered as an available standard option on an additional pin. This can give an indication that a measured current is exceeding its expected value or can switch the power off in the event of a short circuit.
LZSR is offered in a compact size (37.75 x 48.2 x 19.4 mm for each current range) and without compromising the high insulation provided between the primary and measurement circuits. Advanced manufacturing techniques inspired on automotive designs have also been introduced allowing these new transducers to achieve the highest levels of quality and traceability. The LZSR production line has been designed to be a semi-automatic assembling line.
The models are available either with an aperture for the primary conductor (LZSR-P references) or integrating the primary conductor to be soldered on PCB (LZSR-TP references).
They will be well-suited to applications where low offset drift is important, such as in the latest string inverters generation (on the ac side of 70- to 120-kW solar inverters), where standards require a very low dc component in the output current.
Covered by LEM’s five-year warranty, LZSR series current transducers are CE marked and conform to the latest industrial standards.