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The UK rail network is under continuous improvement by the operators, which creates certain demands on the type of DC-DC power converters required. Especially critical is the requirement for suitably isolated units.

The extensive range of DC-DC converters and filters from Mornsun are ideal for the demands of on-board monitoring systems. Train manufacturers and operators share the same goals of striving to make rail travel as safe as possible with the development of data recording equipment covering four principal application areas:

  • On-train data recording (OTDRs) and Remote Condition Monitoring (RCM);
  • Driver Safety Devices (DSD);
  • Driver Interface Units (DIU);
  • Interfacing and accessing on-train electrical and data channels on legacy rolling stock.

The URB1D family of converters from Mornsun is just one of a wide range of DC-DC converters Relec Electronics supply to Arrowvale, which is one of the UKs largest designers and manufacturers of data recording and monitoring devices to the rail industry. Recorders and monitoring devices are used to support accident investigation and have to meet the requirements of systematic safety monitoring procedures, vehicle system analysis, driver training and condition determined maintenance policies.

URBD 1D R3 converters

The URB1D family, a relatively new addition to the portfolio with increased isolation, provides an ideal solution for this type of application.

The units have a 40-160VDC ultra-wide input voltage with 2250VDC reinforced insulation, meeting the requirements of EN60950 and EN50155, and are suitable for operation on 72V, 96V and 110V railway traction supplies. They are typically used to power electronic equipment such as monitoring equipment, and also air-conditioning control and information displays.

They have an operating temperature range of -40°C to +85°C and offer multiple levels of protection (input under-voltage and output short-circuit, over-current, over-voltage protection). The converters come in 2” x 1” standard package with two industry standard pin-out positions available. They can also be supplied in A2S (Chassis mounting) or A4S (DIN-Rail mounting) packages, which have reverse voltage protection built in.

Key features:

  • Ultra-wide voltage range: 40-160VDC;
  • Power rating 6 – 20Watts;
  • 2250VDC reinforced isolation;
  • Operating temperature -40°C to +85°C;
  • Low ripple and noise;
  • International standard pin-outs;
  • Reverse voltage protection available with A2S (chassis mounting), A4S (35mm DIN -rail mounting);
  • Compliant with EN50155/EN60950 and EN50121-3-2.

Long track record

The Railway industry demands especially high performance, flexible yet rugged products and Relec, together with Bel Power Solutions, can look back on over 40 years’ experience in providing power conversion products.

Indeed, the roots of the product range and expertise are to be found in the brand name Melcher, which was originally a Swiss electronics specialist until it became part of the Bel Power Group. The range centres on high performance AC-DC, DC-DC converters, DC-AC inverters and displays and EMC filters compliant with national and international railway standards EN50121-3-2, EN50155.

AC-DC converters are often deployed in lineside applications whilst DC-AC inverters are used to permit onboard AC equipment to be powered by the train’s DC power supply.

Available in a variety of power levels, with a wide range of input and output voltages, the products are designed to operate under extremely wide temperature ranges and include self-cooling enclosed cases.

Operating under what are often very arduous conditions the products have high immunity to electrical, humidity and mechanical stress attributes all of which contribute to delivering extremely high reliability.

Case study

This brief case study illustrates how the experience of the team at Relec was applied successfully to an urgent requirement.

A customer needed to simulate the 110VDC train-borne supply voltage from an AC supply. The solution needed to be quickly available and relatively easy to implement for an urgent requirement. The solution also needed to be robust enough to be installed in a mobile transit case without posing a reliability risk.

The solution

After extended discussions, a solution utilising the Excelsys Ultimod configurable power supply family was selected. The Ultimod series offers field proven reliability, a five-year warranty for peace of mind and, thanks to the flexible/configurable design of the product, the customer could receive their customised solution within 24 hours.

Compliance essential

Product information on the Relec website is comprehensive and the particular standard to which a product is compliant is listed. In addition, the product may also benefit from having been listed by Network Rail PADS (Parts and Drawing System).

Rugged high performance

It is easy to think that displays, hand-held or large, mounted units are ‘standard’ in design and capability, as the majority of us are so used to treating the display on our laptop or PC as typical design standard. Not so!

Rugged Monitor

Relec has over 30 years’ experience in providing monitors and displays for the most arduous of applications. Typical industries and applications served include rail, offshore, defence, marine and construction.

Displays are usually tailor-made to the application and may range in size from 4 inches to 42 inches and may include custom built machined cases.

There is also a vast range of display technologies available to ensure that the product performs whatever may be thrown at it – sometimes literally. The medical industry will demand anti-bacterial coatings, for obvious reasons.

Monitors deployed in high-use areas will need anti-finger-marking treatments and, of a more general nature, other treatments include resistive touch, PCAP and anti-reflective coatings.

EMC filters – essential components

Relec is able to provide the major essential components in order to satisfy the requirements of a typical rail/industrial communication application, a great advantage in being able to provide the client with a broad range of highly qualified technical expertise at a single source.

EMC filters are often required to enable equipment to achieve compliance and operate in demanding environments, and Relec has a comprehensive range of the best EMC filters and chokes available.

The range of filters covers duties from 1A to 1100A for a variety of single and three phase applications, chokes and inductors for noise suppression and transient immunity protection, as well as power entry modules (PEMs) to combine IEC power entry with EMC noise suppression filters and immunity.

Power supply solutions

Relec Electronics is a specialist supplier of electronics solutions specifically selected and designed for applications in the railway industry. With over 38 years’ experience, the company has a highly qualified engineering and QA team to ensure that the most suitable products are selected and can also offer customised design and manufacturing options to give greater flexibility to the range of solutions offered.

The company has been very deliberate and targeted in selecting a strategy of providing specialist products for demanding industries and ensuring that they can offer the best technical support both at the design stage and in after sales service and above all the ability to offer industry compliant products to ensure safe and reliable operation.

Rail Engineer is the leading independent quality monthly magazine for engineers, project managers, directors and leading rail executive decision makers. Head to www.railsubs.com to make a free subscription to RailEngineer magazine or one of its sister publications.


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