Optical indicators and sensors - locate defect in centrally monitored, electrically-controlled systems using switch-over relay

摘要

To facilitate location of defects in, e.g. railway switch points, a glow discharge lamp in series with a high resistor (1000) is connected in parallel with various portions of the control line embracing both whole batteries of units, subsections, and individual equipment units. In case of a line defect a monitor relay (70) releases because of loss of current. The relay may now apply to the line a larger voltage, or it is automatically so applied, causing all the line group flow lamps affected by the defect to be lit. The surveillance principle can also be used for remote control indication of the defect. (DS).