Voltage sensors.

The DVC 1000 series of voltage sensors for insulated nominal voltage measurements in rail traction and industrial applications has been introduced by LEM.

The DVC 1000 series offers panel mounted voltage measurement in a compact package, measuring only 29 x 51 x 89 mm, giving a total volume of only 131.6 cm3.

Designed to measure a nominal voltage of 1000 VRMS, the DVC 1000 series uses an isolating amplifier, providing very high levels of isolation with a safety insulation voltage of 4.2 kV. The use of an isolating amplifier offers significant space savings over other sensors of similar capacity, which use bulky galvanic insulation.

As well as being highly robust, the DVC 1000 series also offers high levels of accuracy and temperature stability. An optional DIN rail mounting adaptor makes it easy to integrate into users’ own applications.

LEM developed the DVC 1000 to be fully compliant with the International Railway Industry Standards (IRIS). Engineers in the railway industry working with both rolling stock and sub-stations can use these versatile new sensors to measure DC links, the output voltages of inverters, the input voltage of 4 quadrant converters, or the battery voltage of Light Rail Vehicles. The features of the DVC 1000 voltage sensors also make them ideal for a broad range of small-to-medium voltage measurements in industrial markets such as DC power supply monitoring, EV chargers and battery storage applications.

DVC 1000 sensors measure voltages by a direct connection on their primary sides, through an internal resistor network and other components designed to feed the signal to an isolation amplifier.

An isolated signal is recovered and then conditioned in order to supply a voltage or a current at the sensor’s output connections, which is an exact representation of the primary voltage. No additional components are needed – the connections are simply connected between the voltage to be measured and the control device.

The DVC 1000 family can supply instantaneous +/- 30 mA current output (DVC 1000) or +/- 10 volt voltage output (DVC 1000-B) at +/- 1500 volt peak. The DVC 1000-UI model supplies a unipolar instantaneous 4-20 mA current output at 0…+1000 Volt DC (Unipolar DC Voltage measurement only).

All models deliver excellent overall accuracy, of +/- 1 % at +25°C with a high stability in temperature, leading to an overall accuracy of +/- 1.7% with an operating temperature range from -40°C to +85°C.

Measurement frequency bandwidth (-3dB point) is 35 kHz and the DVC 1000 models consume only 12 to 22 mA at no primary voltage, depending on the model and the power supply used - from +/- 15 to +/- 24 volt for the DVC 1000 and DVC 1000-B models and from a unipolar +15 to +24 V power supply for the DVC 1000-UI model.

With their compact size and weighing only 57g, the DVC 1000 series is unique on the market. Other key features include compliance to a range of internationally recognised safety standards in addition to their adherence to IRIS specifications. They also exhibit a fast response time of 12 to 17 µs at 90% of nominal voltage.

Designed by LEM in accordance with the latest standards applicable for traction and industry, the DVC 1000 models use materials that comply with all relevant fire and smoke requirements (EN 45545), mandatory in railway applications. They are CE marked and are supplied with a five-year warranty, as are all LEM sensors.

@LEM_Inc @NapierPR #PAuto 

Voltage transducers for the traction market.

The DVM series for insulated nominal voltage measurements in traction applications has been itroduced by LEM. This family of devices spans the range from 600-4200 VRMS and incorporates their proven and patented insulating technology. Despite achieving very high levels of isolation with a safety insulation voltage of 12 kV, the DVM transducer is compact, measuring only 138 x 63.4 x 69 mm.

It is fully compatible and out-performs the previous generation of transducers in terms of functions and performance with new improved levels of accuracy and temperature stability, thus greatly simplifying retrofits.

DVM is also suitable for base mounting, but with slightly different outline dimensions to take into consideration for primary and secondary connections locations for example. The DVM is 30% smaller in height, occupies 25% less volume and is 56% lighter! The reduction in size does not compromise the DVM’s high immunity against the external surrounding perturbations or against the high voltage variations. The new size is also an advantage when confronted with size constraints in modern railway propulsion converters.

LEM developed the DVM 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 DVM voltage transducer also makes it an excellent fit for a broad range of medium to high voltage measurements in industrial markets.

DVM transducers measure voltages by a direct connection on their primary side, transfer the data across an internal isolation barrier and output a current from their secondary side; that is
proportional to the measured voltage thanks to LEM’s patented insulating digital technology. It
delivers an improved typical accuracy, compared to existing products, of +/- 0.5 % at +25°C with a higher stability in temperature. The technology used provides very high levels of immunity to external magnetic fields (almost insensitive) and electromagnetic disturbances (unmatched level). Combined with a highly focused internal electronic design applied on the printed circuit as well as for mechanical design performance reached in common mode condition are exceptional: 0.5% of nominal voltage as error generated with a recovery time of less than 50µs against a voltage of 4200 V applied with a step of 6 kV/us.

Its measurement frequency bandwidth (-3dB point) is 12 kHz and the DVM consumes typically only 30 mA when power supplied under +/-24 VDC (power supply range from +/- 13.5 to +/- 26.4 V DC). 2 kinds of current output ranges are possible either +/- 50 mA, or the standard industrial current-loop range of 4 to 20 mA for unipolar current measurements and one voltage output at 10 V for nominal voltage.

Other key features include a high level of partial discharge extinction voltage (5 kVRMS @ 10 pC) ensuring product long life, and its compliance to a range of internationally-recognised safety standards in addition to its adherence to IRIS specifications. It also exhibits a fast response time. A range of connection configurations, on both the primary and secondary side, increases flexibility for the user.

Designed by LEM in accordance with the latest standards applicable for traction and industry, the DVM uses materials that comply with all relevant fire and smoke requirements that are mandatory in railway applications. It is CE marked and is supplied with a five-year warranty, as are all LEM transducers.

#LEM #Transportation @NapierPR

Voltage proving tool.

Fluke has introduced a new battery powered electronic voltage source that sources both AC and DC voltages for test tool verification.

The new Fluke PRV240 Voltage Proving Unit can be used to test both high and low impedance digital multimeters, clamp meters and Two Pole Testers. It provides a stable, fixed output voltage to properly assess correct operation of many types of electrical tester, clamp meters and multimeters. Verification of a test tool is recommended by both GS38 and NFPA 70E before any live measurements are made.

The Fluke PRV240 Proving Unit is an easy-to-use product for electricians, commercial or industrial technicians, HVAC technicians or anyone working remotely who needs access to a voltage source to verify their tool is working correctly. The PRV240 is the ideal solution for electricians, environmental health and safety managers, plant safety officers (for example at oil & gas and chemical processing plants), facilities managers and other managers concerned with electrical safety and compliance.

The PRV240 comes with a TPAK magnetic hanging strap for convenient operation. It has re-chargeable internal battery power sufficient to perform 5000 verification tests.

Harmonics mitigation!

CP Automation has a new whitepaper that addresses a lack of industry awareness of different methods of harmonic mitigation. It is designed to educate engineers on the most appropriate solutions to mitigate the damage caused by harmonic currents and utility level voltage distortion.

Authored by Jonas Persson, product manager at Comsys AB, Comparing harmonics mitigation techniques (pdf) highlights the challenges facing original equipment manufacturers (OEMs) in tackling the growing problem of harmonic currents. For many years this has held the industry back; the fact that engineers struggle to identify the best solutions for their needs due to a lack of information. The overall context is to reduce harmonic loading in a drive system.

The whitepaper details the four main mitigation techniques and their associated technologies. Covering series passive, series active, shunt passive and shunt active solutions, it presents in-depth case studies of real life implementations of each as well as theoretical worked examples explaining the benefits and drawbacks.

Knowing the different types of mitigation technique to employ is essential. There are three variations of the series-passive solution alone, line reactors, series harmonic filters and multi-phase, each with their own strengths and weaknesses. Choosing one over another is a decision that must be made from an informed perspective.

“Without both breadth and depth of knowledge, it is possible that the most efficient method of harmonic mitigation is being overlooked,” says John Mitchell, business development manager at CP Automation. “On top of that, there are numerous other challenges faced by engineers caused by the rise of non-linear loads, such as extra stresses on outdated equipment.”

“We hope this whitepaper will go some way to addressing the lack of information issue, which in turn will go some way to reducing the amount of harmonics related problems the wider engineering community encounters in electrical industry applications.”

Power saving voltage transducers for the traction market

LEM introduces the DVL series for insulated nominal voltage measurements in traction applications. 

The DVL family of devices from LEM spans the range from 50-2000 VRMS and incorporates LEM’s proven and patented insulating technology. Despite achieving very high levels of isolation with a safety insulation voltage of 8.5 kV, the DVL transducer is compact, measuring only 137.8 x 63 x 64.3 mm. It 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 very 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 in addition to its adherence to IRIS specifications. It also exhibits a fast response time, and excellent noise immunity. A range of connection configurations, on both the primary and secondary side, increases flexibility for the user.

Designed by LEM in accordance with the latest standards applicable for traction, the DVL utilises materials that comply with all relevant fire and smoke requirements, that are mandatory in railway applications. It is CE marked and is supplied with a five-year warranty, as are all LEM railway products.