This allows for a reduced range of models and offers considerable logistical advantages in terms of storage, availability, and price. To compensate for voltage drops, the RMDs feature a 10ms hold time at a 24V input and a 20ms hold time at a 72/110V input. The efficiency of both components is typically 94%. For example, compared to other solutions with an average efficiency of 90%, this translates to a 40% reduction in power losses and heat dissipation in the final application when using RECOM RMD models. That 40% less heat dissipation will undoubtedly extend the product's lifespan!
The components feature a metal housing, an IP20 rating for natural convection, and chassis mounting. They operate from -40°C to +70°C and can withstand 15 minutes of continuous full-power operation at 85°C without derating. Therefore, it is not necessary to oversize the power, as is the case with other solutions that require derating above 55°C or 70°C.
This meets the operating temperature class for rails OT4 and the extended classes ST1 and ST2. Thanks to their excellent efficiency, RMD units can be mounted in any direction without the need for additional heat sinks. A forthcoming "-E" version extends the start-up temperature down to -50°C. Certifications/compliances achieved or pending include EN 50155, EN 50121-3-2 for EMC, EN 50124-1 for insulation coordination, EN 45545-2 hazard level HL1-HL3 for railway fire safety, and IEC/EN 61000-4-2,3,4,5 for EMC. The insulation is reinforced grade, with a rated voltage of 3.5kV AC/5kV DC. The products are Class I equipment and are designed for Category III surge protection (OVC III) environments up to 2000m altitude (OVC II up to 5000m) and pollution degree 2 (PD2). The units are not encapsulated, which reduces weight and saves resources.
Compliance with environmental standards includes EN 60068 for temperature testing and EN 61373 for life, shock, and vibration in Class B body-mount applications. Reliability is also built in, with a calculated MTBF of 1.4 million hours at 40°C according to IEC 61709/UTE C80-810 for the RMD150 and 1.36 million hours for the RMD300. The design life is 20 years, with a nominal lifespan of Class L4, according to EN 50155.
RMD series products feature input reverse polarity and inrush current limiting and are fully protected against input undervoltage and reverse polarity, output overtemperature and overvoltage, overcurrent, and short circuits. An output OR-ing diode is included for connecting outputs in parallel to increase power or redundancy, or for using the RMD unit to charge batteries. Control and monitoring functions include remote ON/OFF, output trim, current sharing pin, and a power OK LED with associated voltage-free contacts.
Marco Kuhn, Plug&Play Product Manager at RECOM, comments: “These are truly plug-and-play products for global rail applications, with their extensive data input, comprehensive specifications, and certifications.”
The parts include a two-year warranty.
