GB605296A - Improvements in or relating to centrally or semi-centrally controlled electric switching systems for the control of public lighting and for other purposes - Google Patents

Abstract

605,296. Switching systems. HORSTMANN, B. G., HORSTMANN, F. O., and HORSTMANN GEAR CO., Ltd. Dec. 19, 1945, No. 34423. [Class 38 (iv)] In an electric power supply system wherein a chain of electromagnetic switches controlling a number of sections of the system operate in cascade in response to a signal supplied from a control station to one of the switches at one end of the chain, the switches are arranged so that a signal can be supplied from the control station to the switch that is normally last in 'the chain, to cause the switches to operate in cascade from the last in the chain to the point in the system where a fault has occurred. Fig. 1 shows sections of the load, e.g. groups of street lamps 1, fed from supply conductors 3, 4, both ends of which are looped into a control station 2. Each switch 5, separating the sections, has a normal control winding 6 connected across the conductors 3, 4 on the side of the switch towards the beginning of the chain and upon closure of a master switch 8 in the control station closes to energize the succeeding section and the normal control winding 6 of. the switch next in the chain, the switching operations then continuing in succession to energize automatically, the whole system. Operation of all switches in the chain is indicated by a circuits normal signal 9 in the control station. Upon the occurrence of a fault, for'instance at point 100, which prevents operation of one or more of the switches, the signal 9 does not function, but an " emergency on " switch 10 in the control station, can be operated to energize the conductors 3, 4 at the end remote from the switch 8 and to energize in succession emergency control windings 7 of the unoperated switches. In Fig. 2 (not shown), each switch 5 comprises two independently operable switching members, controlled by windings 6 and 7 respectively, such that operation of either member disconnects the operating winding of the other. In further arrangements (Figs. 3 and 4, also not shown), the load sections are supplied from a feeder, the electromagnetic switch controlling the supply thereto from the main conductors. In all arrangements, the " emergency on " switch may be arranged to disconnect the circuits normal " signal when the former is operated and alternatively or in addition means 16 may be provided to indicate that that switch has been operated. The master and " emergency on" switches are preferably electromagnetically controlled by switches 17, 18 respectively which may be manually operated or controlled by time switches. The " chain " switches may be provided with delay action devices. The invention is applicable to polyphase systems.