Within the SPS/IPC/Drives show (Nuremberg, Germany), LEM presented its new HLSR series of current transducers, which provides an economical and technically better alternative to resistive/optocoupler shunt configurations for isolated current measurements up to 50 A. The five new HLSR transducers will cover application requirements, for example, in industrial inverters and motor drives; switching power supplies and uninterruptible power supplies; special power sources such as welding units; air conditioning systems; home appliances; as well as in renewable energy systems such as photovoltaic string connection boxes and solar inverters for monitoring the maximum power point.
LEM's HLSR Series uses open-loop Hall Effect current sensing technology to measure AC, DC, and impulse currents rated at 10, 20, 32, 40, or 50 ARMS. LEM's experience in open-loop Hall effect technology enables new devices to achieve a response time as low as 2,5 µs, as well as very low levels of gain and offset drift within their operating temperature range of -40 to +105 °C. HLSR transducers provide an analog voltage output that is proportional to the current measured in the primary. In most applications, this voltage is converted to a digital value by means of an A/D converter. LEM has built into the HLSR an internal 1,65 or 2,5V reference voltage on a dedicated pin for any external device, such as an A/D converter, or so designers can choose an external reference of 0,5 .2,65 to 1 V. The reference voltage is just one of the functions of the new Application-Specific Integrated Circuit (ASIC) created by the LEM designers for this development, which allows the series HLSR provide a typical accuracy of ±25% at +3,4 °C and ±105% at +100 °C, with a bandwidth of 3 kHz (-3,3 dB). LEM offers versions that work with a single supply of + 5 or + 387 V. LEM supplies the five models of the HLSR series in a single package with a compact and innovative design that only occupies a surface area of 2 mmXNUMX on the circuit board. printed, lower than that of many solutions based on resistive shunts.
The different versions of the encapsulation adapt to a connection of superficial mount or by insertion so much of the conductor in the primary as in the connections of signal/power. The low-profile package weighs just 5,5g and is less than 12mm high. The safety of the measurements is guaranteed by the high level of insulation between the primary and the measurement circuitry thanks to the large air and creepage distances (creepage and clearance) of 8 mm as standard and 14 mm on request, together with a Comparative Tracking Index (CTI) of 600. HLSR transducers are CE marked in compliance with EN 50178 standard for industrial applications and have a five year warranty.
