11:1 and 12:1 ultra-wide input DC/DCs for ‘plug and play’ worldwide rail applications.
Fully railway-compliant, highly efficient and cost-effective DC/DCs are now available from RECOM with their new RMD150 and RMD300 products, rated at 150W and 300W respectively. With a single fully regulated output (24V or others, e.g. 110V), each product has an ultra-wide input range of 16.8V to 137V continuous, to include all common global railway nominals. The input range extends down to 14.4V for 100ms and up to 154V for 1 second, to ride through the dips and surges specified in rail standard EN 50155. This allows to reduce the variety of models and brings considerably logistic advantages for stocking, availability and price conditions. To allow for supply dropouts, the RMDs features 10ms hold-up at 24V input, and 20ms at 72/110 input. Efficiency for both parts is typically 94%. As an example, against other solutions with an average efficiency of 90%, this means a reduction of power losses and heat dissipation in the end-application of 40% by using the RECOM RMD-Models. 40% less heat dissipation will undoubtfully expand the life time!
The parts are metal cased, IP20-rated for natural convection, chassis mounting. The parts are working from -40°C to +70°C and to 85°C for 15 minutes at full power continuously without derating. Thus, no power over-dimensioning is necessary, as with other solutions which need to derate above 55°C or 70°C. This meets the rail operating temperature Class OT4 and extended Classes ST1 and ST2. Due to the excellent efficiency the RMD units can be mounted in any direction without the need of additional heat sinks. An ‘-E’ version coming soon, extends the startup temperature down to -50°C. Certifications/compliance 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. Isolation is reinforced grade, rated 3.5kVAC/5kVDC. The products are equipment Class I and are designed for over-voltage category III (OVC III) to 2000m altitude (OVCII to 5000m) and pollution degree 2 (PD2) environments. The units are not encapsulated, which reduces the weight and safes resources. Environmental standards compliance includes EN 60068 for temperature testing and EN 61373 for life, shock and vibration in Class B body-mount applications. Reliability is also designed-in with a calculated MTBF of 1.4M hrs at 40°C according to IEC 61709/UTE C80-810 for the RMD150 and 1.36MHrs for the RMD300. Design lifetime is 20 years, rated useful life class L4, according to EN 50155.
The RMD series products have input reverse polarity and inrush limitation and are fully protected against input under-voltage and reverse polarity, over-temperature and output over-voltage, over-current and short circuits. An output OR-ing diode is included for paralleling outputs for increased power or redundancy or to use the RMD unit to charge batteries. Control and monitoring features include remote ON/OFF, output trim, current share pin, and a Power OK LED with associated volt-free contacts.
Marco Kuhn, product manager Plug&Play of RECOM comments: “These are truly ‘plug and play’ products for global railway applications with their wide input, comprehensive specifications and certifications”.
Parts include a two-year warranty. Samples and OEM pricing are available from all authorized distributors, or directly from RECOM.
