DC/DC Converters with Protection Degree IP65 for Railway Applications
It is a general problem: a failure in the electronics usually leads to a larger problem in the complete system. The search for a replacement for the failed electronic component often is a special challenge. Creative thinking and a little customisation are required if an electronic component fails in an area with special demands on the environmental conditions. This is a scenario that is all too common in the railway industry.
The simple fact is that the rail environment is tough on electronics. So many of the standard devices used in other industries can fail when confronted by the daily operational realities of vibration, dirt, contamination and high-voltage transients.
Take the example of a power supply used to drive an on-board Train Protection and Warning System (TPWS). The unit has to provide a good fit for the system’s electrical and mechanical specifications and requires – first and foremost – operational reliability.
The primary-switched DC/DC converters PCMDS150WK-IP65 from MTM Power are specially designed for applications in vehicle and rail technology. The standard version of this supply solution features patented thermoselective vacuum encapsulation and an IP65 rating for maximum protection against external contaminants.
The thermoselective vacuum encapsulation process (EP 1 987 708, U.S. Patent No. 8, 821, 778 B2) completely and permanently encapsulates the power supply to create a cemented joint to provide an inseparable link between the potting material and the components. This ensures that ageing, heat, cold, rapid temperature changes and other environmental influences do not result in delamination, cracking or air pockets, which can compromise reliability and potentially lead to failure. Thermoselective vacuum encapsulation guarantees uniform heat dissipation within the modules as well as excellent resistance against environmental influences such as shock, vibration and moisture. Remarkable features of this DC/DC converter are the profile of the casing made of black anodised aluminium with a heat sink and its connection via special rugged industrial connectors according to protection degree IP65. Thus they are compliant with EN 60 068-2-1/2-2/2-11/2-14/2- 30.
The push-pull topology used while developing these converters enables a wide input voltage range with high efficiency. The 150 W converters are available with a wide input range for battery voltages of 24 V, 36 V, 48 V, 60 V, 72 V, 80 V, 96 V and 110 V acc. to EN 50 155. With the help of a transformer and a secondary linear choke, a galvanically isolated output voltage of 24 V is produced which is adjusted by pulse-width modulation according to the current mode principle. The dimensions are 192 x 115 x 68mm (length x width x height).
The converters need no ground load and are short circuit-protected by primary and secondary power limiting. The converters are maintenance-free, prepared for the use in devices with Protection Class II and fulfil the low voltage directive. They feature a mechanically and electrically rugged design using SMD technology and undergo an automatic piece-by-piece test. Cooling is achieved by free convection.
In recent years, MTM Power has increasingly developed into one of the largest power supply manufacturers for railway applications in Europe. The decisive factor here is the quality of innovative products and the flexibility and reliability of the company business. MTM Power products meet all relevant standards and VDE/EN/UL regulations where applicable. The wide range of EN 50155-compliant DC/DC converters with 30 – 600 W are designed especially for vehicle and railway applications. Particularly for the sophisticated use in trains, these devices supply the electric and electronic systems on board and trackside. Besides these rail converters, the product range includes DC/AC inverters, filters and multi-power supply systems.