| 摘要 |
393,939. Railway signalling systems. BRITISH POWER RAILWAY SIGNAL CO., Ltd., Windsor Works, Slough, Buckinghamshire, GLENN, S. L., 3, Central Buildings, London, and TATTERSALL, A. E., Hayton House, Knapton Lane, Acomb, Yorkshire. Dec. 8, 1931, No. 34047. [Class 105.] In an alternating-current track circuit signalling system with two-element relays, a phase-modifying device is inserted in the connection between the supply and the rails to adjust the phase between the two elements of the relay so that the change of phase which occurs on shunting by a train still further reduces or even reverses the torque reduced by the shunting of the current. Fig. 2 shows the track winding 8 of the relay fed over the track rails 3, 4 by a constant current transformer having two primary windings 13, 14 with the desired phase adjustment obtained by including a condenser 15 in series with the winding 13. In the arrangement shown in Fig. 3 the phase adjustment is effected by a resistance-shunted condenser 20 in series with the two transformer primaries 13, 14. The switch 23 permits the resistance to be altered to suit different ballast conditions. When the relay has to be at some distance from the rails a step-up transformer is used to feed the track winding. The relay may be at the feed end of the section 3, 4 as shown in Fig. 4 with its track winding 8 in series with the phase adjusting device 31. The remote end of the section is bridged by a transformer-connected condenser 32. Specification 385,666 is referred to. |
