Electro-pneumatic control for train brakes - has bridge network to compare signals and differential amplifier to reduce hysteresis

摘要

The pneumatic brake pressure of the train brakes are monitored by a set of sensors whose output signal is applied to one arm of a Wheatstone bridge network, with another arm supplied with the command signal from the brake control lever. THe output from the bridge is passed to a differential amplifier where it is compared with correction signals, to generate the accurate correction signals to regulate the brake pressure. The system eliminates the hysteresis associated with relay-operated brake controls, as well as the instability of purely differential amplifier control, which can lead to large deviations from the control signals. The resulting brake control has smooth and fast response.