Product Categories

Our battery chargers are a solid basis for stabilizing railway vehicles’ on-board supplies. The devices are suitable for all common one- or three-phase VAC input voltages. They guarantee separated supply for battery and on-board consumers and come up with numerous safety features that you can customize according to your wishes – for example with a CAN bus interface.

At Grau Elektronik’s, this product category covers the high voltage range from 750 V_DC up to 3000 V_DC: On the one hand, well-established converters for contact wires, that are made for providing 24 or 110 V at railway crossings, using the 750 V_DC contact wire’s voltage. What is special and very practical about it: The devices are meant to be inserted and kept running directly at the contact wire, without any additional transient filters or external fuses. On the other hand, our reliable emergency starting equipment, for 1500 V_DC and 3000 V_DC applications: They are able to provide downstream devices and their control electronics in a safe way in the case of a deep discharged battery, as well as to initiate a system start at any time, using contact wire voltage.

Our capacitor charging devices are the product of choice when it comes to stabilize DC link voltage systems. The voltage/current control at the converter’s output is the basis for DC link capacitors’ safe charging, as it is used for example in locomotives and tramways for emergency compressor supplies or for providing energy reserves for system-critical shutdown processes.

In rail vehicles, the 15kV~ and 25kV~ 50Hz supply voltages are adapted and converted specifically for the on-board power supply—including electric motors, battery chargers, and power system structures—using transformers and converter circuits. From the very high vehicle supply currents and voltages, appropriately scaled currents and voltages are generated for evaluation by measuring instruments as well as diagnostic and electronic evaluation systems. This is achieved via current and voltage transformers with specifically selected transformation ratios. In this process, high demands are placed on linearity across the entire railway temperature range. Internal consumption must not distort the measurement results, as the energy consumption of the various vehicles needs to be recorded as accurately as possible. Measurement is carried out via on-board Energy Measurement Systems (EMS) using VTB and CTB measuring transformers. Grau Elektronik offers solutions for supply frequencies of both 16 2/3 Hz and 50 Hz.

Our wide range of voltage converter products offers you numerous solutions for both DC and AC input voltages when it comes to provide downstream electronics in a safe way. Designed for a long lifetime up to 20 years (according to EN50155), they prevent reliably sudden voltage drops or dynamic fluctuations of on-board voltages, using their internal energy storage circuits. Thus, control units, sensor circuits, actuators or drive units in vehicles are solidly provided by the converters’ controlled output voltage – even under very harsh conditions as they are prevailing in railroad operations.

You can also rely completely on us for choosing your right power supply: Countless applications, just as softstarting electric motors or providing solenoid valves, require a highly available current source. For realizing that, Grau Elektronik offers you current- or voltage-controlled converters that can be used with different V_DC or V_AC input voltages. The output powers range from 50 W up to 55 kW (for controlled rectifiers).

They come into use where primarily only V_DC voltages are available on board railway vehicles. However, for running common electric devices, V_AC voltage is needed: Hence, plugs in the vehicle can be used based on battery voltage, even building up an own 230 V_AC onboard network would be an option. In practice, the inverters will provide for example laptops, cleaning equipment or V_AC fans, one- or three phase with very high crest factor. The products from this category even allow for the setup of an interruptible power supply – in connection with our battery chargers for example.

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