Braking resistor

This article deals with the braking resistor in electrical engineering. See braking resistance (mountaineering) for devices used in sport climbing .

The braking resistor is a load resistor in resistance brakes or when operating a frequency converter . In the generator operation of the motor, it represents a load that loads and brakes the motor.

Resistance brake on railways

Braking resistors on the roof of a locomotive Ae 6/8 of the Bern-Lötschberg-Simplon-Bahn . The energy generated by the electric brake is converted into heat in the braking resistors.

In the case of resistance brakes, braking resistors are used to convert the electrical power of the traction motors , which are switched as generators , of electric or diesel-electric traction vehicles or of trolleybuses into waste heat. The braking resistors can be installed on the roof, in the passenger compartment or under the vehicle. For cooling, braking resistors are either provided with their own fans or they are self-ventilated.

Consideration of the braking system with converter

When operating a motor with a converter, two operating modes are considered:

1. the motor operation when driving a load and
2. generator operation when braking the motor.

While the speed setpoint is being reduced by the frequency converter, the motor works as a generator and supplies energy to the frequency converter, which is then collected in the intermediate circuit. The voltage in the intermediate circuit would continue to rise until the failure of components or their insulation and the associated increased current flow trigger the corresponding fuse and interrupt the circuit . The braking resistor represents a consumer for the intermediate circuit and absorbs the braking energy. Such high loads can be braked quickly with a braking resistor. Braking resistors are used, for example, in industry, rail technology and wind turbines.

Individual evidence

1. ^ Zarko Filipovic: Electric railways . 4th revised edition, Springer Verlag, Berlin Heidelberg New York 2005, ISBN 3-540-21310-4
2. ↑ European patent specification: Self-ventilated braking resistor No. EP 1 074 026 B1 ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (accessed on March 13, 2012; PDF; 47 kB). 
3. ↑ braking resistors. In: Website of the company Frizlen, Murr. Retrieved May 6, 2017 .