High accuracy transducer for trackside applications

21st October 2021

LEM

James Anstee

0 0

LEM has introduced a new current transducer series, that can be used for retrofitting trackside applications or for reducing the cost of new installations. Due to its robust design and standardised 4-20 mA out, it can also be used in automation or the control of PV-plants. The transducer’s innovative primary circuit (patent pending), in combination with two ASiCs to detect the magnetic field, enables precise current measurement.

The HTRS-series will be available in three current ranges (10 A / 30 A / 50 A), with peak current measurement up to twice that of nominal. Despite the very high insulation test voltage of 6.0 kV, the HTRS-series is compact, measuring 72 mm x 29 mm x 26 mm. The HTRS series offers temperature stability, while mounting adapters allow the unit to be installed in existing applications.

The transducer complies with the International Railway Industry Standards (IRIS). With the HTRS, users in the field of railway technology have a versatile series of sensors at their disposal, regardless of whether they work in the field of rail or signalling technology. The HTRS series is suitable for measuring currents in point machines, crossing gates and signalling systems. It can also be used in industrial applications, such as process automation or DC current collection in solar parks.

A split core design offers a very high overall accuracy of 2% at +25 °C and high temperature stability in the operating temperature range between -40 and +85 °C. The HTRS has a measuring frequency bandwidth ( -3 dB point) of 1 kHz and also offers a fast response time of 10 μs at 90% of the rated current. The current consumption at maximum primary current is less than 50 mA at a supply voltage of +12 V_DC or +24 V_DC.

Thanks to the primary circuit the maximum deviation caused by neighbouring conductors with the same current is only around 0.3%. The positioning error of the primary conductor is negligibly small compared to previous solutions.

Weighing only 35 g, the transducer is more than 70% lighter than previous split core current transducers for such applications. Other performance features include compliance with various internationally recognised railway standards as well as IRIS specifications.

The current sensor has been designed to the latest standards for railway technology and industry, including UL and UKCE,and is based on materials that meet all relevant fire protection requirements for railway applications. A CE certificate is available and, like all LEM current transducers for railway applications, the HTRS series comes with a LEM warranty of five years.