It is fully compatible and surpasses the previous generation of transducers in terms of features and performance with new and improved levels of accuracy and temperature stability, which greatly simplifies device replacement.
The DVM is also suitable for mounting on a base, but with slightly different external dimensions to accommodate, for example, the location of the primary and secondary connections. The DVM is 30% shorter, has a 25% smaller volume, and is 56% lighter. This size reduction does not compromise the DVM's high immunity to external disturbances or large voltage variations. The new size is also advantageous given the size limitations of modern railway propulsion converters.
LEM has developed the DVM series to fully comply with IRIS (International Railway Industry Standards), providing railway engineers working with rolling stock and substations with a versatile new transducer equally suitable for measuring mains voltages or DC connections to the main converter on board trains. The DVM voltage transducer's capabilities make it ideal for a wide range of medium- and high-voltage measurements in industrial markets.
DVM transducers measure voltages via a direct connection on their primary side, transfer the data through an internal isolation barrier, and supply a current from their secondary side that is proportional to the measured voltage, thanks to LEM's patented digital isolation technology. This offers improved accuracy compared to existing products, typically +/- 0.5% at +25°C, with greater temperature stability. The technology employed provides very high levels of immunity to external magnetic fields (it is virtually insensitive) and electromagnetic interference (unmatched). When combined with a highly specialized internal electronic design applied to both the printed circuit board and mechanical design, the common-mode performance is exceptional: 0.5% of the nominal voltage as generated error with a recovery time of less than 50 µs against a voltage of 4200 V applied with a step rate of 6 kV/µs.
Its measurement frequency bandwidth (-3dB point) is 12 kHz, and the DVM typically consumes only 30 mA when powered below +/-24 VDC (the power supply range is +/-13.5 to +/-26.4 VDC). It offers two output current ranges:
+/-50 mA or the industry-standard range of 4 to 20 mA for single-pole current measurements, and a 10 V output voltage for the nominal voltage.
Other important features include its high partial discharge extinction voltage
(5 kVRMS at 10 pC), which ensures a long product lifespan, as well as its compatibility with numerous international safety standards and its compliance with IRIS specifications. It also stands out for its fast response time. Its various connection configurations, on both the primary and secondary sides, provide the user with greater flexibility.
The DVM, designed by LEM in accordance with the latest traction and industry standards, uses materials that meet all relevant fire and smoke protection requirements, which are mandatory for railway applications. It is CE marked and comes with a five-year warranty, like all LEM transducers.
