Auxiliary converter
An auxiliary converter ( HBU ) or on- board power converter is the term used to describe the power converter of a traction vehicle that ensures the supply of the auxiliary units with electrical energy. For the traction motors , however, is the traction converter responsible. With the development of auxiliary converters made it possible in a simple and low-wear, a three-phase introduce -Bordnetz so -phase asynchronous motors with squirrel-cage rotor can be used as drives for the auxiliary units. Compared to single-phase series motors , due to the lack of a commutator , these have lower acquisition and maintenance costs, a lower mass, a lower space requirement and are more robust. If the mains voltage of the auxiliary converter is set to the usual voltage level of the low-voltage network (in Europe for example 230/400 volts), commercially available electrical devices can be used.
In the case of electric traction vehicles in alternating current networks, the auxiliary converter is usually fed from a special tap on the main transformer ; in direct current networks directly from the contact line . Modern diesel traction vehicles with electrical power transmission in converter technology are also equipped with auxiliary converters. The inverter of the auxiliary converter is fed directly from the intermediate circuit of the traction converter.
For reasons of redundancy, many modern traction vehicles are equipped with three-phase AC technology with two auxiliary converters. This makes it possible to set up two separate three-phase networks. An auxiliary converter works with a variable frequency and supplies the load-dependent, variable-speed consumers (traction motor fan, cooling system fan, etc.), which means that they can be controlled as required, which saves energy and reduces noise. The second auxiliary converter works at a constant frequency and supplies all other consumers. If an auxiliary converter fails, the entire supply is carried out by the remaining auxiliary converter at a constant frequency.
Before the converter was introduced, the auxiliaries in AC traction vehicles were supplied with single-phase alternating current from a special tap on the main transformer, or in direct current traction vehicles with direct current from the contact line. If three-phase current was to be used to power the auxiliary systems, this had to be generated by a rotating converter or, in the case of 50 Hz networks, by means of an Arnó converter .
Typical ancillary units
- Compressed air supply ( air compressor for generating compressed air, among other things for the brakes )
- Cooling devices (drive motor fans, fans for oil and water coolers , oil and water pumps, etc.)
- Electrical supply to the on-board network
- Battery charger (on some AC vehicles, the battery charger is also supplied via a separate transformer tap)
- air conditioning
Individual evidence
- ↑ a b c Bendel Helmut: The electric locomotive: structure, function, new technology . 2., arr. and additional edition Transpress, Berlin 1994, ISBN 3-344-70844-9 .
- ^ A b Filipović Žarko: Electric railways . 5th edition 2015. Springer Berlin Heidelberg, Berlin, Heidelberg 2015, ISBN 978-3-642-45227-7 .