Drives and Controls Magazine

Prime contender for better current measurements

01 June, 2003

Prime contender for better current measurements

The electrical measurements specialist LEM has developed a split-core AC current transducer that uses a novel sensing principle said deliver better performance than devices based on magnetic circuits. The DIN-rail-mounting transducer also has a new mechanical design, claimed to cut installation times.

The AP and APR current transducers are based on a patented sensing technology called Prime (Planar Rogowski I MEasurement) which is being used for the first time in industrial automation. The technology is said to be immune from saturation caused by over-currents, and to deliver an absolute accuracy of better than 0.8% over a wide range of inputs, as well as a 1kHz bandwidth.

The non-contacting transducers offer user-selectable measuring ranges from 10-400A and a choice of outputs (4-20mA, 0-5V or 0-10V). The APR models provide true-RMS measurements for non-linear loads or noisy environments.