Bel Power Solutions HR Series of DC-DC converters represents versatile power supplies ideally suitable for use in transportation and other advanced electronic systems. Features include a very broad input voltage range, very high efficiency, high reliability, low output voltage noise, and excellent dynamic response to load/line changes. They can be connected to all conventional railway batteries.

The converter inputs are protected against surges and transients. An input over- and under-voltage lockout circuitry disables the outputs if the input voltage is outside of the specified range. To avoid high input current at operation with high-voltage batteries, the inhibit input allows for adjusting of the under-voltage lockout to a suitable level, therefore allowing the use of an appropriate input fuse.

The converters exhibit an inrush current limiter, preventing circuit breakers and fuses from tripping at switch-on.

The outputs are open- and short-circuit proof. Full input-to-output, input-to-case, output-to-case, and output-to-output isolation are provided. The converters are particularly suitable for railway applications, and can be supplied by all common railway batteries of 24, 36, 48, 72, 96, 110 and 120 V nominal. The converters comply with EN 50155 and EN 50121-3-2. All boards are coated with a protective lacquer.

The case design allows operation at nominal load up to 71°C with natural cooling. If forced cooling is provided, the ambient temperature may exceed 71°C, but the case temperature must remain below 95°C.

A temperature sensor generates an inhibit signal, which disables the outputs when the case temperature TC exceeds the limit. The outputs are automatically re-enabled when the temperature drops below the limit. LED indicators display the status of the converter and allow for visual monitoring of the system at any time.

The converters may either be plugged into a 19" rack system according to IEC 60297-3, or be chassis mounted. Two heat sinks of different size and cooling plates for chassis mounting (option B, B1) are available.