Transportation Engineering / Train Resistors
Following the state of the art, rail-bound vehicles are equipped with three-phase current motors whose acceleration, speed and braking are controlled by means of power electronics. During braking, the kinetic energy of the vehicle is transformed into electrical energy, returned to the grid wherever possible, and thus reused. However, this requires a grid that can take on such energy at any time. Otherwise, the grid voltage would simply rise and the brakes will not work. Another method is to convert the braking energy into heat using a braking resistor.
Braking resistors are used as
additional brake for energy return to the grid,
to take off some stress from the mechanical brake
and as an emergency brake resistor.
Electrical braking is wear-free and can be optimally controlled so that no abrupt changes in braking occur which the passengers may resent.
In view of the large amounts of heat to be dissipated, braking resistors require sufficient cooling air. Depending on the cooling type
natural air cooling and
forced air cooling
braking resistors are available.
NATURAL AIR COOLING
resistors are mainly installed on the outside of the vehicle aned in some cases the airstream can effectively support cooling.
GINO Verkehrstechnik - Dachwiderstand für SelbstkühlungRooftop resistor for natural air cooling
FORCED AIR COOLING
braking resistors are supplied with cooling air by a fan so that mounting inside of the vehicle is also possible.
GINO Verkehrstechnik - nterflurwiderstand mit VentilatorkühlungUnderfloor resistor with fan cooling
Among the resistors mounted on the outside of the vehicles, two types are available:
GINO Verkehrstechnik - Dachwiderstand
Rooftop resistors and GINO Verkehrstechnik - Unterflurwiderstand
Rooftop resistors are often easier to cool but mostly result in aerodynamic and optical problems.
Underfloor resistors are problematic in terms of heat dissipation, in particular during standstill after braking.