Monitoring of voltage signals used to control railway relay circuit - has voltages generated by separate transformers with outputs to phase comparator based circuit controlling relay.

摘要

One transformer (1) provides an auxiliary voltage while a second (2) provides a control voltage. Both transformers have a number of secondary windings (3, 4) and one transformer has voltages phase-shifted by 90 degrees relative to the those of the other. A pair of monitoring circuits (5) have inputs (6, 7) coupled to the secondary windings and the outputs (10) correct with the coils of electromechanical relays (11). The relays have at least one contact (12) coupled to a circuit (13) controlling a main relay. The monitoring circuit is based upon phase comparison of the voltage signals used to generate a difference signal that is integrated and used by the relays. USE/ADVANTAGE - Railway control systems. Fast response and high accuracy.