New series of compact, power saving voltage transducers target traction market applications

September 18, 2012 // By Paul Buckley
LEM has introduced the DVL series for insulated nominal voltage measurements in traction applications. This family of devices spans the range from 50-2000 VRMS and incorporates LEM’s proven and patented insulating technology.

Despite achieving high levels of isolation with a safety insulation voltage of 8.5 kV, the DVL transducer is compact, measuring 137.8 x 63 x 64.3 mm.  The series is fully compatible with previous generations of transducers in terms of both functions, performance and footprint and offers new high levels of accuracy and temperature stability.

LEM developed the DVL to be fully compliant with the International Railway Industry Standards (IRIS), providing engineers in the railway industry, who are working with both rolling stock and sub-stations, with a versatile new transducer that is equally applicable to measuring network voltages, or the main converter DC link on-board trains. The feature set of the DVL voltage transducer also makes it an excellent fit for a broad range of small-to-medium voltage measurements in industrial markets.

DVL transducers measures voltages by a direct connection on its primary side, transfers the data across an internal isolation barrier and outputs a current from its secondary side that is proportional to the measured voltage thanks to LEM’s patented insulating digital technology. It delivers an improved overall accuracy, compared to existing products, of  +/- 0.4 % at +25°C with a higher stability in temperature: The technology used provides high levels of immunity to external magnetic fields (almost insensitive) and electromagnetic disturbances (unmatched level). Its measurement frequency bandwidth (-3dB point) is 14 kHz and the DVL consumes only 20 to 25 mA when power supplied under +/-24 VDC (power supply range from +/- 13.5 to +/- 26.4 V), a power saving of 30% relative its predecessors. 2 kinds of current output ranges are possible either +/- 50 mA, or the standard industrial current-loop range of 4 to 20 mA.

In addition to using less power the DVL, in its small outline, is 30% lighter than transducers already in the market. Other key features include a high level of partial discharge extinction voltage, and compliance to a range of internationally-recognised safety standards