| 摘要 |
Alternating current track circuit apparatus is provided for obtaining optimum shunting sensitivity throughout a stretch of track divided by insulated joints into adjoining double rail track circuits and having impedance bonds at respective transmitting and receiving ends. An alternating current track feed is connected to the track rails at the transmitting end of each of the track circuits through a circuit tuned to resonance by a capacitor connected in series with a winding of the impedance bond at that end for energization of the associated track circuit from a source of alternating current. An alternating current receiver is provided for connection to the track rails at the receiving end of each of the track circuits through a circuit tuned to resonance by a capacitor in series with a winding of another of the impedance bonds and a track winding of a receiving relay for sensing the presence of a vehicle in the associated track section. The receiver comprises a local source of energy derived from the same source as the transmitting apparatus and connected to a local winding of the relay in series with a variable capacitor for adjusting of the phase difference between energization of the track and local windings for providing optimum sensitivity of the relay. |
