Temperature Measurement System for Train Rheostat

This paper describes the development of a novel system for temperature measurement of train rheostats. These high resistances are used in train wagons to dissipate the power used to supply the train when it is braking. When it happens rheostat may reach temperature higher than 1000 degrees C and then, if not controlled, may damage the train roof, falling in the cabins below. In order to prevent this event, some temperature measurement systems based on thermocouples, removing the power from the rheostat when the temperature reaches a threshold, are placed inside the train roof. These systems unfortunately are not reliable due to problems of maintenance during the train lifespan. In order to do this measurement without adding other sensors that need to be maintained, the temperature is calculated from the rheostat resistance variation exploited by the current and the voltage that are always measured inside the train by its monitor system.