Equipment manufacturers of propulsion systems for railway vehicles always, face the problem that there is any need for short time peak power availability switching magneto-inductive loads (circuit breakers) direct from catenary input voltage.

Pursuant to the experience of Grau Elektronik, different nominal input voltages can be found between 750V and 3,000V, including the tolerances and transients requested by the railway standards. In general, there is no need to combine different voltage ranges in the same application. However, a wider input voltage range covering several rated catenary voltages allows for substantial advantages regarding testing and approving of sub-systems.

Grau Elektronik Germany has developed a product to satisfy this scenario. Traditional FDB and NSB converter series of DC / DC converters are split in up to four input voltage ranges. In addition, this one converter type exhibits an extremely wide input voltage range of 7 to 1. Input voltage range is 700V to 5,075V. Output power up to 300W.

The FDB and NSB Series comply with the railway standards EN 50155, EN 50163, EN 50121-3-2.

A special challenge for the design engineers was to include a short time peak power capability of factor 6:1. With this feature, a converter connected to a catenary input voltage, 1,000V… 3,000V, is able to energise power switch relays for control and Switch ON/OFF inductive motors motors. Due to the high output current, safe switching is possible without battery voltages.

Grau Elektronik products have been used for more than 16 years in railway applications. This German Company was founded in 2001 and is specialised in customized railway converter solutions.

The FDB and NSB converters offer isolated outputs 24V, 36V or 110V with an output power 75W continuous up to 1,500W peak power.