RECOM - Experts & Thought Leaders

The wide variety of electrical power distribution infrastructure methods that exist around the world hosts many challenges for power engineers designing products that rely on high-voltage power sources. However, regardless of the power distribution infrastructure method, high transient voltages are present in the electrical power distribution systems simply by the nature of their power sources. Transient voltages can be caused by a release in stored energy, from a variety of sources including the toggling of generators, arcing, lightning strikes, etc. IEC 60204-1 standard Electrical kit connected to the power distribution systems from dangerous and detrimental conditions To protect the electrical equipment connected to the power distribution systems from the dangerous and detrimental conditions that can be created by transient voltages, the International Electrotechnical Commission (IEC) implemented the IEC 60204-1 standard as a means of categorizing devices by their ability to tolerate transients and setting conditional category requirements.  This standard, titled "Safety of Machinery - Electrical Equipment of Machines - Part 1: General Requirements," identifies four categories of magnitude-based transient voltage tolerance at different operating voltages. Table 1: Transient Voltage tolerance at different operating voltages This chart outlines different working voltages and the tolerated transient voltage thresholds sorted by category. For example, if a device that operates at 300Vs is able to withstand 4000 transient volts, it would be considered a Category III device. Overvoltage Category (OVC) Requirements The main purpose of the IEC-60204-1, however, is to set condition-based requirements for devices to achieve a specific category rating to ensure safe use. As shown in the table above, all power devices and wiring must be categorized by an OVC ranking. As shown in the table above, all power devices and wiring must be categorized by an OVC ranking Based on the connection conditions that the device is subjected to, it may be required by the IEC to meet a specific OVC rating. For example, if a piece of robotics machinery is directly connected to a distribution panel, the IEC-60204 requires the wiring connecting the panel and devices to be OVC III, and the power supply within the robotic machinery to be rated OVC III as well. OVC III isolation transformer Alternatively, if the robotic machinery power supply is not able to meet OVC III ratings, an OVC III isolation transformer must be installed in between the distribution panel and the robotic machinery. In doing so, the isolation transformer steps down the voltage from the distribution panel, and subsequently lowers the category requirement for the robotic machinery power supply and wiring to OVC II. In many instances similar to this, the selection of power supply can have cost and space implications for the equipment owner, whereby they may be required to have additional isolation equipment to support end-user specifications. Installation categories The installation categories, as defined by IEC 60204-1:2016, ordered from least likely to see high-voltage transients to most likely to see high-voltage transients, are as follows: Category I requirements apply to equipment connected to circuits in which measures are taken to limit transient or short-duration overvoltage to a low level, such as circuits that are protected from transients/overvoltage conditions. Category II requirements apply to energy-consuming equipment to be supplied from a fixed installation such as appliances, portable tools, household loads, outlets, lighting, and connections more than 10m away from a Category III source. Category III requirements apply to equipment in fixed installations, and where the reliability and the availability of the equipment are subject to special requirements, such as isolation transformers, switch gears, and equipment directly wired to a distribution panel. Category IV requirements apply to equipment used at the origin of the installation to the power grid, such as electricity meters, overcurrent protection systems, utility transformers, and distribution panels. In Category IV applications, high-voltage transients are very likely. OVC III Power Supplies Use of qualified OVC power supplies in the correct circumstances proves to be distinctly advantageous For obvious financial reasons, a system that does not require supplemental equipment to support its use has a significant competitive distinction over alternative products. Additionally, part count reduction in critical applications mitigates the possible points of failure, and the use of qualified OVC power supplies in the correct circumstances proves to be distinctly advantageous. For example, RECOM’s RAC05-K/480 series and RAC03E-K/277 series of AC/DC power supplies both are qualified for OVC III use with an ultrawide input range. While the RAC05-K/480 offers an input range of 100-480VAC nominal and an output of 5W, with an isolation of 4kV, and an output voltage of 5, 12, or 15V.  The cost-efficient RAC03E-K/277 has an input range of nominal 100VAC to enhanced 277VAC, which makes it suitable for worldwide applications in automation control, industry 4.0, IoT, and household automation. The RAC05-K/480 can be directly wired to a distribution panel for use in a variety of applications that require 5V, such as smart grid, renewable energy, smart metering, and Internet of Things (IoT) applications. RECOM’s RAC10-K/277 series If an application demands more power, RECOM’s RAC10-K/277 series is capable of outputting 10W with an input voltage range of 85V-277V, and output voltages of 3.3V-24V. The power supplies of both RAC05-K and RAC10-K are ideal for applications with always-on and standby mode operations, such as process automation, IoT, and smart building systems. Additionally, the RAC20-K/277 series can be built on a project-specific basis to meet OVC III requirements as well as the RACM40-K series. Use of OVC III qualified power supplies in always-on IoT applications reduces overall cost of ownership, BOM, product complexity, and installation requirements, and can make your product distinguished from the competition.

For over two centuries, railways and the rolling stock that make train travel possible have evolved from mechanical steam-powered locomotives to the current high-tech trains, packed with sophisticated safety, traction, communication, and information systems, for various applications ranging from signals and environmental monitoring to communication and driving electrical motors. The need for railway-approved power supplies has never been greater. power supplies in railway Whether on a train, track, or station, power supplies used in railway applications are regularly exposed to extremely harsh conditions, while also being expected to work accurately and reliably. The expected lifespan of these products is decades long, with extreme working conditions including heat, cold, shock & vibration, mechanical impact, and EMI, all of which can cause serious damage to the electronic assemblies of power converters. Rugged power converters Power supplies must also meet the highest standards, including for shock and vibration Rugged power converters that can withstand all of these harsh conditions are critical when designing railway systems. To qualify for use in railway systems, power supplies must also meet the highest standards, including for shock and vibration, fire protection, thermal, EMI/ESD, weight, and safety and reliability. Strict Railway Standards Today, several stringent international standards regulate railway applications. Some of these include: EN 50155 - Electronic equipment used on rolling stock EN 61373 - Shock and vibration tests EN 50121-3-2 - Electromagnetic Compatibility (EMC) EN 45545-2 - Fire Protection on Railway Vehicles EN50155 EN50155, for instance, is a well-known performance standard for electronic equipment used in rolling stock (All rail vehicles that move, including locomotives, passenger wagons, light railways, and freight trains). Besides laying down minimum requirements for the input voltage range, electrical isolation, operating temperature range, shock and vibration, humidity, and EMC, it also specifies equipment reliability and expected useful life. operational life and environmental testing EN50155 standard also mandates normal operating temperature tests as well as thermal cycling In many cases, electronic equipment used on rolling stock is expected to have more than 20 years of operational life, demanding thorough environmental testing. Additionally, the EN50155 standard also mandates normal operating temperature tests as well as thermal cycling, dry heat, and damp heat tests. EN 61373, EN 50121-3-2, EN 45545-2 EN 61373, on the other hand, specifies the requirements for testing equipment intended for use on railway vehicles which may be subject to vibrations and shock owing to the nature of the railway operational environment. EN 50121-3-2 applies to the emission and immunity aspects of EMC for electrical and electronic apparatus intended for use on railway rolling stock. To achieve the highest level of safety possible in the event of a fire, all materials used in rail vehicles must comply with the European standard EN 45545-2. High-Power DC/DC Converters RECOM offers customized power solutions of up to 10kW for railways Applying over 40 years of experience in developing and manufacturing leading standard and custom power converters, RECOM recently expanded its product portfolio of EN50155-certified power supplies. With the acquisition of the Italian power specialist Power Control Systems, RECOM offers customized power solutions of up to 10kW for railways, alongside a broad range of AC/DC and DC/DC converters. standard voltage ratings Several different supply voltages have emerged for DC/DC converters used in railway systems in the last few decades. The standard voltage ratings are 24VDC, 36VDC, 48VDC, 72VDC, 96VDC, and 110VDC. The latest version of EN50155 defines seven different standardized DC voltages, although 110VDC is most common for long-distance trains, and 24VDC through 48VDC is more typical on light railways, trams, and trolleys. range of input voltage RP20-FR and RP40-FR cover the nominal input voltage range including transients, with three different input voltage To meet the requirements for nominal 24, 48, or 110VDC input voltages, many railway application developers opt for 4:1 converters, such as the RP20-FR and RP40-FR series, as they cover the nominal input voltage range including transients, with three different input voltage versions. Recent improvements at RECOM have opened new doors for railway designers needing to cover a wider range of input voltage with only one converter type. 100W and 200W DC/DC converters The company’s latest 100W and 200W DC/DC converters from the RPA100H and RPA200H families feature a broad 10:1 input range to cover all common voltage ratings in one module. With ultra-wide input from 14.4VDC to 156VDC, these DC/DC converters can be considered for any railway design without worrying about voltage tolerances, voltage dips, or the local supply voltage. 12V or 24VDC output Utilizing a metal baseplate, these converters operate over a wide temperature range, from -40°C to +97°C RECOM also offers isolated and regulated 12V or 24VDC output with consistently high efficiency of up to 90% over the entire input voltage and load range. Utilizing a metal baseplate, these converters operate over a wide temperature range, from -40°C to +97°C. RP40Q-RUW and RP60Q-RUW series The RP40Q-RUW and RP60Q-RUW series go beyond the current ultra-wide input to accept a 12:1 input range, from 14 to 185VDC, offering designers even more options. These converters, housed in a standard quarter-brick case, are fitted with threaded inserts for secure mounting in high shock and vibration environments. Additionally, they provide reinforced isolation at 3VDC, regulated 5VDC, 12VDC, 15VDC, 24VDC, and 48VDC output with sense and trim pins. They are CE marked, offer EN50155 and EN45545-2 certification, and come with a three-year warranty. 8W to 240W DC/DC converters RECOM has also developed an RMD plug-and-play series for higher-power railway applications RECOM's expanded portfolio of DC/DC converters from 8W to 240W for the railway industry offers the broadest range of EN50155-certified products on the market. These railway-certified series are housed in compact case sizes to deliver a power density of up to 4.5W/cm3, one of the highest available.  RECOM has also developed an RMD plug-and-play series for higher power railway applications, which provides 150W to 500W of output power with five input ranges covering 14.4V to 170VDC, tested to railway standard EN 50155 and ready to go as complete solutions. AC/DC and DC/AC Inverters In the AC/DC arena, RECOM and its subsidiary Power Control Systems have developed three-phase AC input battery chargers with active power factor correction (PFC) and railway standard compliance. Available with ratings of 3.2kW (SA3200 series) and 5kW (SA5000 series), the converters can be cascaded to generate up to 20kW. The SA3200 series also operates with DC input up to 800V. Both series are available with output from 24VDC up to 110VDC (and all in between 36/48/72/96VDC). ID250 series The series complies with railway application standards and is typically used to provide power for passenger sockets For applications that need AC supply, the company offers inverter families, like the ID250 series from Power Control Systems, that deliver single-phase or multiphase output voltage or current with 24V, 48V, 72V, or 110VDC nominal input. Output is single-phase 200-240VAC or 50-156VAC for the 48V input version. The series complies with railway application standards and is typically used to provide power for passenger sockets or driver consoles. Conclusion Around the world, as railway networks expand to serve the rising transportation needs of workers, tourists, and industry, the demand for rugged and standards-compliant power supplies continues to increase. As an experienced and pioneering provider of high-performance power supplies, RECOM is a reliable source for a broad range of rugged and standards-compliant DC/DC and AC/DC converters and DC/AC inverters. Power Control Systems RECOM and its subsidiary Power Control Systems have established a broad portfolio of rugged EN 50155-compliant power converters, including complete turnkey solutions, for many railway applications. From low-power (8W-240W) modules up to 10kW power supplies, RECOM has a range of standard and custom solutions for all railway needs.

RECOM strengthened its distribution network in Japan with the addition of Midoriya Electric, specializing in AC/DC, DC/DC converters, switching regulators, and LED drivers. Yosuke Sato, Director & General Manager, 1st International Division, Midoriya Electric, expressed, “RECOM's product portfolio has very good synergy with our other line cards. We are very excited about expanding sales of RECOM products.” ideal distribution partner According to Jordi Torrebadell, Director of RECOM Power Japan, Midoriya Electric is an ideal distribution partner due to its experience, market knowledge, extensive sales force, and strong brand recognition in Japan.  Jordi Torrebadell adds, “Midoriya Electric's strengths make them an excellent fit for our extensive portfolio of over 30,000 compact power supplies. We are excited to have them on board and certainly look forward to a successful partnership.”