CIRCUIT FOR DETECTING UNBALANCE OF THE TRACTION CURRENT IN A TRACK CIRCUIT

摘要

ABSTRACT OF THE DISCLOSURE:In order to prevent the production of a false signalby a device for detecting the presence of rolling stock on atrack section, when a rail is earthed or fractured, a circuitis provided for detecting unbalance of a traction currentflowing through a track circuit formed by said track section.The unbalance detecting circuit is used in combination witha transmitter generating a track circuit current supplied to the trackcircuit and with an associated receiver. The unbalance detectingcircuit has two current sensors which are connected to theends of the rails of the track section adjacent to the receiverfor producing respective signals representative of the currentsflowing through said rails, this unbalance detecting circuit transmittinga track circuit signal produced by the track circuit currentto the receiver only when the currents detected by the currentsensors are equal or when their difference is small enoughto cause no undue excitation of the receiver. The detectingdevice is further provided with a pole change switch connectedbetween the transmitter generating the track circuit currentand the ends of the rails associated therewith for cyclicallyreversing the direction of said track circuit current.